diff --git a/engine/src/flutter/tests/TestExpectations b/engine/src/flutter/tests/TestExpectations
index a1cf018b72..7743092e3b 100644
--- a/engine/src/flutter/tests/TestExpectations
+++ b/engine/src/flutter/tests/TestExpectations
@@ -1,10 +1,4 @@
 
-# These tests require gc() to be exposed.
-crbug.com/1 mutation-observer/observer-wrapper-dropoff-transient.sky [ Skip ]
-crbug.com/1 mutation-observer/observer-wrapper-dropoff.sky [ Skip ]
-crbug.com/1 mutation-observer/transient-gc-crash.sky [ Skip ]
-crbug.com/1 mutation-observer/weak-callback-gc-crash.sky [ Skip ]
-
 # These tests need more basic testing support plumbed right into the
 # platform, which we don't currently have:
 https://github.com/domokit/mojo/issues/15 parser/cr.sky [ Skip ]
@@ -16,29 +10,12 @@ https://github.com/domokit/mojo/issues/14 parser/normaliser-null.sky [ Skip ]
 https://github.com/domokit/mojo/issues/14 parser/utf16.sky [ Skip ]
 https://github.com/domokit/mojo/issues/16 parser/normaliser-crlf.sky [ Skip ]
 
-# These tests are flaky on the bots
-https://github.com/domokit/mojo/issues/24 custom-elements/constructor-calls-created-synchronously.sky [ Skip ]
-https://github.com/domokit/mojo/issues/24 mutation-observer/observe-attributes.sky [ Skip ]
-
+# We don't implement embed ViewManagerClient yet.
 crbug.com/2 services/iframe-embed-vmc.sky [ Skip ]
 
-# This test only fails on the bots:
-#crbug.com/434822 inspector/page-agent-get-resource-tree.sky [ Pass Failure ]
-
 # These tests broke during the Dart migration
 crbug.com/2 animation/basic-imperative.sky [ Skip ]
 crbug.com/2 animation/basic-transition.sky [ Skip ]
-crbug.com/2 custom-elements/document-register-basic.sky [ Skip ]
-crbug.com/2 custom-elements/document-register-reentrant-null-constructor.sky [ Skip ]
-crbug.com/2 custom-elements/document-register-reentrant-returning-fake.sky [ Skip ]
-crbug.com/2 custom-elements/document-register-reentrant-throwing-constructor.sky [ Skip ]
-crbug.com/2 custom-elements/element-upgrade-no-register-and-leak.sky [ Skip ]
-crbug.com/2 custom-elements/generated-constructor.sky [ Skip ]
-crbug.com/2 custom-elements/html-element-type-extension-assert.sky [ Skip ]
-crbug.com/2 custom-elements/lifecycle-created-createElement-recursion.sky [ Skip ]
-crbug.com/2 custom-elements/lifecycle-created-createElement-reentrancy.sky [ Skip ]
-crbug.com/2 custom-elements/lifecycle-created-parser-script.sky [ Skip ]
-crbug.com/2 custom-elements/resources/document-register-fuzz.sky [ Skip ]
 crbug.com/2 editing/backspace.sky [ Skip ]
 crbug.com/2 editing/delete_block_contents.sky [ Skip ]
 crbug.com/2 editing/replace.sky [ Skip ]
@@ -58,47 +35,15 @@ crbug.com/2 framework/xmlhttprequest/unicode-post.sky [ Skip ]
 crbug.com/2 framework/xmlhttprequest/xhr-does-not-exist.sky [ Skip ]
 crbug.com/2 framework/xmlhttprequest/xhr-relative.sky [ Skip ]
 crbug.com/2 framework/xmlhttprequest/xhr.sky [ Skip ]
-crbug.com/2 inspector/css-computed-style.sky [ Skip ]
-crbug.com/2 inspector/dom-mutation-modify-text-node-and-append.sky [ Skip ]
-crbug.com/2 inspector/dom-mutation.sky [ Skip ]
-crbug.com/2 inspector/page-agent-get-resource-tree.sky [ Skip ]
-crbug.com/2 js/classes.sky [ Skip ]
 crbug.com/2 layout/margins-absolute.sky [ Skip ]
 crbug.com/2 layout/margins.sky [ Skip ]
 crbug.com/2 lowlevel/createElement.sky [ Skip ]
-crbug.com/2 mocha/describe-only.sky [ Skip ]
-crbug.com/2 mocha/it-only.sky [ Skip ]
 crbug.com/2 modules/application.sky [ Skip ]
 crbug.com/2 modules/instance-of-application.sky [ Skip ]
 crbug.com/2 modules/instance-of-module.sky [ Skip ]
 crbug.com/2 modules/load-event.sky [ Skip ]
 crbug.com/2 modules/modules.sky [ Skip ]
-crbug.com/2 modules/resources/does-not-export.sky [ Skip ]
-crbug.com/2 modules/resources/instance-of-module-module.sky [ Skip ]
-crbug.com/2 modules/resources/intermediate.sky [ Skip ]
-crbug.com/2 modules/resources/pass.sky [ Skip ]
 crbug.com/2 modules/script-import.sky [ Skip ]
-crbug.com/2 mutation-observer/callback-arguments.sky [ Skip ]
-crbug.com/2 mutation-observer/clear-transient-without-delivery.sky [ Skip ]
-crbug.com/2 mutation-observer/create-during-delivery.sky [ Skip ]
-crbug.com/2 mutation-observer/cross-document.sky [ Skip ]
-crbug.com/2 mutation-observer/delivery-order.sky [ Skip ]
-crbug.com/2 mutation-observer/disconnect-cancel-pending.sky [ Skip ]
-crbug.com/2 mutation-observer/document-fragment-insertion.sky [ Skip ]
-crbug.com/2 mutation-observer/mutate-during-delivery.sky [ Skip ]
-crbug.com/2 mutation-observer/mutation-callback-non-element-crash.sky [ Skip ]
-crbug.com/2 mutation-observer/mutation-observer-constructor.sky [ Skip ]
-crbug.com/2 mutation-observer/mutation-record-constructor.sky [ Skip ]
-crbug.com/2 mutation-observer/mutation-record-nullity.sky [ Skip ]
-crbug.com/2 mutation-observer/observe-characterdata.sky [ Skip ]
-crbug.com/2 mutation-observer/observe-childList.sky [ Skip ]
-crbug.com/2 mutation-observer/observe-exceptions.sky [ Skip ]
-crbug.com/2 mutation-observer/observe-options-attributes.sky [ Skip ]
-crbug.com/2 mutation-observer/observe-options-character-data.sky [ Skip ]
-crbug.com/2 mutation-observer/observe-subtree.sky [ Skip ]
-crbug.com/2 mutation-observer/script-append.sky [ Skip ]
-crbug.com/2 mutation-observer/shadow-dom.sky [ Skip ]
-crbug.com/2 mutation-observer/takeRecords.sky [ Skip ]
 crbug.com/2 parser/script.sky [ Skip ]
 crbug.com/2 services/buffer.sky [ Skip ]
 crbug.com/2 services/codec.sky [ Skip ]
diff --git a/engine/src/flutter/tests/custom-elements/constructor-calls-created-synchronously-expected.txt b/engine/src/flutter/tests/custom-elements/constructor-calls-created-synchronously-expected.txt
deleted file mode 100644
index affd6723ed..0000000000
--- a/engine/src/flutter/tests/custom-elements/constructor-calls-created-synchronously-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 Custom element constructors should run the createdCallback synchronously
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/custom-elements/constructor-calls-created-synchronously.sky b/engine/src/flutter/tests/custom-elements/constructor-calls-created-synchronously.sky
deleted file mode 100644
index 39aa5ca699..0000000000
--- a/engine/src/flutter/tests/custom-elements/constructor-calls-created-synchronously.sky
+++ /dev/null
@@ -1,21 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<body>
-<div id="container"></div>
-<script>
-describe('Custom element constructors', function() {
-  it('should run the createdCallback synchronously', function() {
-    var proto = Object.create(HTMLElement.prototype);
-    var ncallbacks = 0;
-    proto.createdCallback = function () {
-      ncallbacks++;
-    };
-    var A = document.registerElement('x-a', {prototype: proto});
-    var x = new A();
-    assert.equal(ncallbacks, 1);
-  });
-});
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/document-register-basic-expected.txt b/engine/src/flutter/tests/custom-elements/document-register-basic-expected.txt
deleted file mode 100644
index 2b979afdc8..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-basic-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 document.registerElement() should have basic behaviors
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/custom-elements/document-register-basic.sky b/engine/src/flutter/tests/custom-elements/document-register-basic.sky
deleted file mode 100644
index 6679362fb6..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-basic.sky
+++ /dev/null
@@ -1,101 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<body>
-<div id="container"></div>
-<script>
-describe('document.registerElement()', function() {
-  it('should have basic behaviors', function() {
-    function createRegisterParameters()
-    {
-        return {
-            prototype: Object.create(HTMLElement.prototype, { thisIsPrototype: { value: true } })
-        };
-    }
-
-    var fooConstructor = document.registerElement('x-foo', createRegisterParameters());
-    assert.equal(typeof fooConstructor, "function");
-    assert.equal(fooConstructor.prototype.__proto__, HTMLElement.prototype);
-    assert.ok(fooConstructor.prototype.thisIsPrototype);
-
-    // Bad prototype: prototype is already a built-in interface prototype object
-    assert.throws(function() {
-        document.registerElement("x-bad-a", HTMLElement)
-    });
-    // Bad prototype: prototype is already a Custom Element interface prototype object
-    assert.throws(function() {
-        document.registerElement("x-bad-b", fooConstructor)
-    });
-    // Bad prototype: 'constructor' is not configurable
-    var proto = Object.create(HTMLElement.prototype, {
-      constructor: {configurable: false, writable: true}
-    });
-    assert.throws(function() {
-        document.registerElement("x-bad-c", { prototype: proto })
-    });
-    // Call as function
-    assert.throws(function() {
-        fooConstructor()
-    })
-
-    // Constructor initiated instantiation
-    var createdFoo = new fooConstructor();
-
-    // JS built-in properties
-    assert.equal(createdFoo.__proto__, fooConstructor.prototype);
-    assert.equal(createdFoo.constructor, fooConstructor);
-
-    // Native getter
-    assert.equal(createdFoo.tagName, "x-foo");
-
-    // Native setter
-    createdFoo.textContent = 'Hello';
-    assert.equal(createdFoo.textContent, "Hello");
-
-    // Native method
-    var childDiv = document.createElement('div');
-    createdFoo.appendChild(childDiv);
-    assert.equal(createdFoo.lastChild, childDiv);
-
-    // Parser initiated instantiation
-    var container = document.getElementById('container');
-    container.appendChild(document.createElement("x-foo"));
-    var parsedFoo = container.firstChild;
-
-    assert.equal(parsedFoo.__proto__, fooConstructor.prototype);
-    assert.equal(parsedFoo.tagName, "x-foo");
-
-    // Ensuring the wrapper is retained
-    parsedFoo.someProperty = 'hello';
-    assert.equal(parsedFoo.someProperty, container.firstChild.someProperty);
-
-    // Having another constructor
-    var barConstructor = document.registerElement('x-bar', createRegisterParameters());
-    assert.ok('barConstructor !== fooConstructor');
-    var createdBar = new barConstructor();
-    assert.equal(createdBar.tagName, "x-bar");
-
-    // Having a subclass
-    var bazConstructor = document.registerElement('x-baz', { prototype: Object.create(fooConstructor.prototype, { thisIsAlsoPrototype: { value: true } }) });
-    var createdBaz = new bazConstructor();
-    assert.equal(createdBaz.tagName, "x-baz");
-    assert.ok(createdBaz.thisIsPrototype);
-    assert.ok(createdBaz.thisIsAlsoPrototype);
-
-    // With irregular cases
-    var createdUpperBar = document.createElement('X-BAR');
-    var createdMixedBar = document.createElement('X-Bar');
-    assert.notEqual(createdUpperBar.constructor, barConstructor);
-    assert.notEqual(createdUpperBar.tagName, "x-bar");
-    assert.notEqual(createdMixedBar.constructor, barConstructor);
-    assert.notEqual(createdMixedBar.tagName, "x-bar");
-
-    // Constructors shouldn't interfere with each other
-    assert.equal((new fooConstructor).tagName, "x-foo");
-    assert.equal((new barConstructor).tagName, "x-bar");
-    assert.equal((new bazConstructor).tagName, "x-baz");
-  });
-});
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/document-register-reentrant-null-constructor-expected.txt b/engine/src/flutter/tests/custom-elements/document-register-reentrant-null-constructor-expected.txt
deleted file mode 100644
index d583723293..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-reentrant-null-constructor-expected.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-CONSOLE: LOG: Constructor object isn't created.
-Fuzzing document.registerElement() through getters. PASS unless crash.
diff --git a/engine/src/flutter/tests/custom-elements/document-register-reentrant-null-constructor.sky b/engine/src/flutter/tests/custom-elements/document-register-reentrant-null-constructor.sky
deleted file mode 100644
index b455f9d484..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-reentrant-null-constructor.sky
+++ /dev/null
@@ -1,18 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<import src="resources/document-register-fuzz.sky" as="fuzzer" />
-<body>
-<div id="container"></div>
-Fuzzing document.registerElement() through getters. PASS unless crash.
-<script>
-fuzzer.setupObjectHooks({
-    prototypeGet: function() { },
-    prototypeSet: function(value) { },
-    constructorGet: function() { },
-    constructorSet: function(value) { }
-});
-
-fuzzer.exerciseDocumentRegister();
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/document-register-reentrant-returning-fake-expected.txt b/engine/src/flutter/tests/custom-elements/document-register-reentrant-returning-fake-expected.txt
deleted file mode 100644
index 6a159f7199..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-reentrant-returning-fake-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-Fuzzing document.registerElement() through getters. PASS uless crash.
diff --git a/engine/src/flutter/tests/custom-elements/document-register-reentrant-returning-fake.sky b/engine/src/flutter/tests/custom-elements/document-register-reentrant-returning-fake.sky
deleted file mode 100644
index 3b616f032f..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-reentrant-returning-fake.sky
+++ /dev/null
@@ -1,21 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<import src="resources/document-register-fuzz.sky" as="fuzzer" />
-<body>
-<div id="container"></div>
-Fuzzing document.registerElement() through getters. PASS uless crash.
-<script>
-var badPrototype = Image.prototype;
-var badConstructor = Image.prototype.constructor;
-
-fuzzer.setupObjectHooks({
-    prototypeGet: function() { return badPrototype; },
-    prototypeSet: function(value) {  },
-    constructorGet: function() { return badConstructor; },
-    constructorSet: function(value) {  }
-});
-
-fuzzer.exerciseDocumentRegister();
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/document-register-reentrant-throwing-constructor-expected.txt b/engine/src/flutter/tests/custom-elements/document-register-reentrant-throwing-constructor-expected.txt
deleted file mode 100644
index d583723293..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-reentrant-throwing-constructor-expected.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-CONSOLE: LOG: Constructor object isn't created.
-Fuzzing document.registerElement() through getters. PASS unless crash.
diff --git a/engine/src/flutter/tests/custom-elements/document-register-reentrant-throwing-constructor.sky b/engine/src/flutter/tests/custom-elements/document-register-reentrant-throwing-constructor.sky
deleted file mode 100644
index 56848976e1..0000000000
--- a/engine/src/flutter/tests/custom-elements/document-register-reentrant-throwing-constructor.sky
+++ /dev/null
@@ -1,18 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<import src="resources/document-register-fuzz.sky" as="fuzzer" />
-<body>
-<div id="container"></div>
-Fuzzing document.registerElement() through getters. PASS unless crash.
-<script>
-fuzzer.setupObjectHooks({
-    prototypeGet: function() { throw "Error"; },
-    prototypeSet: function(value) { throw "Error"; },
-    constructorGet: function() { throw "Error"; },
-    constructorSet: function(value) { throw "Error"; }
-});
-
-fuzzer.exerciseDocumentRegister();
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/element-upgrade-no-register-and-leak-expected.txt b/engine/src/flutter/tests/custom-elements/element-upgrade-no-register-and-leak-expected.txt
deleted file mode 100644
index 32ca4b58ed..0000000000
--- a/engine/src/flutter/tests/custom-elements/element-upgrade-no-register-and-leak-expected.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-Tests unresolved element not leaking if never resolved.
-
diff --git a/engine/src/flutter/tests/custom-elements/element-upgrade-no-register-and-leak.sky b/engine/src/flutter/tests/custom-elements/element-upgrade-no-register-and-leak.sky
deleted file mode 100644
index 64a19165b5..0000000000
--- a/engine/src/flutter/tests/custom-elements/element-upgrade-no-register-and-leak.sky
+++ /dev/null
@@ -1,13 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<body>
-Tests unresolved element not leaking if never resolved.
-<div id="container"></div>
-<script>
-// Verify that a custom tag for which no element is ever registered
-// doesn't cause a document nor elements to leak.
-var host = document.createElement('div');
-host.appendChild(document.createElement('x-a'));
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/generated-constructor-expected.txt b/engine/src/flutter/tests/custom-elements/generated-constructor-expected.txt
deleted file mode 100644
index 458b095a91..0000000000
--- a/engine/src/flutter/tests/custom-elements/generated-constructor-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 Custom element constructor should inherit from the passed constructor
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/custom-elements/generated-constructor.sky b/engine/src/flutter/tests/custom-elements/generated-constructor.sky
deleted file mode 100644
index bbfd289000..0000000000
--- a/engine/src/flutter/tests/custom-elements/generated-constructor.sky
+++ /dev/null
@@ -1,19 +0,0 @@
-<html>
-<import src="../resources/mocha.sky" />
-<import src="../resources/chai.sky" />
-<script>
-describe("Custom element constructor", function() {
-  it("should inherit from the passed constructor", function() {
-    class TestElementClass extends HTMLElement {
-      static test() { return 10; }
-    }
-    var TestElement = document.registerElement("test-element-1", {
-      prototype: TestElementClass.prototype,
-    });
-    assert.isFunction(TestElement.test);
-    assert.equal(TestElement.test(), 10);
-    assert.equal(Object.getPrototypeOf(TestElement), TestElementClass);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/html-element-type-extension-assert-expected.txt b/engine/src/flutter/tests/custom-elements/html-element-type-extension-assert-expected.txt
deleted file mode 100644
index 5712a16936..0000000000
--- a/engine/src/flutter/tests/custom-elements/html-element-type-extension-assert-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-Tests that type extension of a element whose DOM interface is HTMLElement does not assert
diff --git a/engine/src/flutter/tests/custom-elements/html-element-type-extension-assert.sky b/engine/src/flutter/tests/custom-elements/html-element-type-extension-assert.sky
deleted file mode 100644
index 812c5f64b6..0000000000
--- a/engine/src/flutter/tests/custom-elements/html-element-type-extension-assert.sky
+++ /dev/null
@@ -1,11 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<body>
-<section id="a" is="x-a"></section>
-Tests that type extension of a element whose DOM interface is HTMLElement does not assert
-<script>
-var u = document.querySelector('#a');
-var v = document.createElement('section', 'x-a');
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-recursion-expected.txt b/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-recursion-expected.txt
deleted file mode 100644
index 1a143ed11e..0000000000
--- a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-recursion-expected.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-CONSOLE: LOG: PASS unless crash
-
diff --git a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-recursion.sky b/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-recursion.sky
deleted file mode 100644
index 360ed92b84..0000000000
--- a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-recursion.sky
+++ /dev/null
@@ -1,10 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<body>
-<script>
-document.registerElement("x-foo", { prototype: Object.create(HTMLElement.prototype, { createdCallback: { value: function () { this.innerHTML = "<x-foo>Hello</x-foo>"; } } }) });
-document.createElement("x-foo");
-console.log("PASS unless crash");
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-reentrancy-expected.txt b/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-reentrancy-expected.txt
deleted file mode 100644
index f0e1695908..0000000000
--- a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-reentrancy-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-This test ensures that is visible in following script block.
diff --git a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-reentrancy.sky b/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-reentrancy.sky
deleted file mode 100644
index 8e90dce0a5..0000000000
--- a/engine/src/flutter/tests/custom-elements/lifecycle-created-createElement-reentrancy.sky
+++ /dev/null
@@ -1,29 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<import src="../resources/chai.sky" />
-<body>
-This test ensures that  is visible in following script block.
-<script>
-window.callbacksCalled = [];
-
-function fooCreatedFunction() {
-  assert.deepEqual(window.callbacksCalled, []);
-  window.callbacksCalled.push(this.tagName);
-  this.appendChild(document.createElement("x-bar"));
-  assert.deepEqual(window.callbacksCalled, ['x-foo', 'x-bar']);
-}
-
-function barCreatedFunction() {
-  assert.deepEqual(window.callbacksCalled, ['x-foo']);
-  window.callbacksCalled.push(this.tagName);
-}
-
-document.registerElement("x-foo", { prototype: Object.create(HTMLElement.prototype, { createdCallback: { value: fooCreatedFunction } }) });
-document.registerElement("x-bar", { prototype: Object.create(HTMLElement.prototype, { createdCallback: { value: barCreatedFunction } }) });
-</script>
-<script>
-document.createElement("x-foo");
-assert.deepEqual(window.callbacksCalled, ['x-foo', 'x-bar']);
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/lifecycle-created-parser-script-expected.txt b/engine/src/flutter/tests/custom-elements/lifecycle-created-parser-script-expected.txt
deleted file mode 100644
index 4e962ea021..0000000000
--- a/engine/src/flutter/tests/custom-elements/lifecycle-created-parser-script-expected.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-This test ensures that the lifecycle callback of a parser-made element is visible in following script block.
-
diff --git a/engine/src/flutter/tests/custom-elements/lifecycle-created-parser-script.sky b/engine/src/flutter/tests/custom-elements/lifecycle-created-parser-script.sky
deleted file mode 100644
index 85dbfaaec5..0000000000
--- a/engine/src/flutter/tests/custom-elements/lifecycle-created-parser-script.sky
+++ /dev/null
@@ -1,15 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<import src="../resources/chai.sky" />
-<body>
-This test ensures that the lifecycle callback of a parser-made element is visible in following script block.
-<script>
-var proto = Object.create(HTMLElement.prototype, { createdCallback: { value: function() { window.callbacksCalled = true; } } });
-document.registerElement("x-foo", { prototype: proto });
-</script>
-<x-foo></x-foo>
-<script>
-assert.ok("window.callbacksCalled");
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/custom-elements/resources/document-register-fuzz.sky b/engine/src/flutter/tests/custom-elements/resources/document-register-fuzz.sky
deleted file mode 100644
index 494af737dd..0000000000
--- a/engine/src/flutter/tests/custom-elements/resources/document-register-fuzz.sky
+++ /dev/null
@@ -1,60 +0,0 @@
-<script>
-function setupObjectHooks(hooks)
-{
-    // Wrapper for these object should be materialized before setting hooks.
-    console.log;
-    document.register;
-
-    Object.defineProperty(Object.prototype, "prototype", {
-        get: function() { return hooks.prototypeGet(); },
-        set: function(value) { return hooks.prototypeSet(value); }
-    });
-
-    Object.defineProperty(Object.prototype, "constructor", {
-        get: function() { return hooks.constructorGet(); },
-        set: function(value) { return hooks.constructorSet(value); }
-    });
-
-    return hooks;
-}
-
-function exerciseDocumentRegister()
-{
-    register('x-a', {});
-    register('x-b', {prototype: Object.create(HTMLElement.prototype)});
-}
-
-function register(name, options)
-{
-    var myConstructor = null;
-    try {
-        myConstructor = document.registerElement(name, options);
-    } catch (e) { }
-
-    try {
-        if (!myConstructor) {
-            console.log("Constructor object isn't created.");
-            return;
-        }
-
-        if (myConstructor.prototype != options.prototype) {
-            console.log("FAIL: bad prototype");
-            return;
-         }
-
-        var element = new myConstructor();
-        if (!element)
-            return;
-        if (element.constructor != myConstructor) {
-            console.log("FAIL: bad constructor");
-            return;
-         }
-    } catch (e) { console.log(e); }
-}
-
-module.exports = {
-    setupObjectHooks: setupObjectHooks,
-    exerciseDocumentRegister: exerciseDocumentRegister,
-    register: register,
-}
-</script>
diff --git a/engine/src/flutter/tests/inspector/css-computed-style-expected.txt b/engine/src/flutter/tests/inspector/css-computed-style-expected.txt
deleted file mode 100644
index 76f5a5a5aa..0000000000
--- a/engine/src/flutter/tests/inspector/css-computed-style-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-Done!
diff --git a/engine/src/flutter/tests/inspector/css-computed-style.sky b/engine/src/flutter/tests/inspector/css-computed-style.sky
deleted file mode 100644
index f85b3bb367..0000000000
--- a/engine/src/flutter/tests/inspector/css-computed-style.sky
+++ /dev/null
@@ -1,18 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="/sky/framework/inspector/css-agent.sky" as="CSSAgent" />
-<script>
-var fakeDOMAgent = {
-  getNodeForId: function(id) {
-    return document.documentElement;
-  }
-};
-
-var cssAgent = new CSSAgent(fakeDOMAgent);
-cssAgent.enable();
-var response = cssAgent.getComputedStyleForNode({nodeId: '1'});
-
-assert.isTrue(response["computedStyle"].length > 0);
-internals.notifyTestComplete("Done!");
-</script>
-</html>
diff --git a/engine/src/flutter/tests/inspector/dom-mutation-expected.txt b/engine/src/flutter/tests/inspector/dom-mutation-expected.txt
deleted file mode 100644
index 76f5a5a5aa..0000000000
--- a/engine/src/flutter/tests/inspector/dom-mutation-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-Done!
diff --git a/engine/src/flutter/tests/inspector/dom-mutation-modify-text-node-and-append-expected.txt b/engine/src/flutter/tests/inspector/dom-mutation-modify-text-node-and-append-expected.txt
deleted file mode 100644
index 52eaf21c30..0000000000
--- a/engine/src/flutter/tests/inspector/dom-mutation-modify-text-node-and-append-expected.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-CONSOLE: LOG: DOM.childNodeInserted
-CONSOLE: LOG: 2
-CONSOLE: LOG: 3
-CONSOLE: LOG: DOM.childNodeInserted
-CONSOLE: LOG: 3
-adding
diff --git a/engine/src/flutter/tests/inspector/dom-mutation-modify-text-node-and-append.sky b/engine/src/flutter/tests/inspector/dom-mutation-modify-text-node-and-append.sky
deleted file mode 100644
index b5e32ac8fa..0000000000
--- a/engine/src/flutter/tests/inspector/dom-mutation-modify-text-node-and-append.sky
+++ /dev/null
@@ -1,34 +0,0 @@
-<html>
-<import src="/sky/framework/inspector/dom-agent.sky" as="DOMAgent" />
-<div></div>
-<script>
-// FIXME: This shows a bug in our DOM mutation handling, we should
-// only get one childNodeInserted record here, but we get two, which
-// means the inspector shows two nodes where it should only show one.
-
-// setTimeout to flush pending DOM modifications and measure
-// only the changes we want to.
-setTimeout(function() {
-    var delegate = {
-        sendMessage: function(message, params) {
-            console.log(message);
-            if (params.node)
-                console.log(params.node.nodeId);
-            if (params.node && params.node.children)
-                console.log(params.node.children[0].nodeId);
-        }
-    };
-
-    var domAgent = new DOMAgent(delegate);
-    domAgent.enable();
-
-    var adding = document.createElement('adding');
-    document.querySelector('div').appendChild(adding);
-    adding.textContent = 'adding';
-
-    setTimeout(function() {
-        internals.notifyTestComplete(internals.contentAsText());
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/inspector/dom-mutation.sky b/engine/src/flutter/tests/inspector/dom-mutation.sky
deleted file mode 100644
index 8c6f1aed44..0000000000
--- a/engine/src/flutter/tests/inspector/dom-mutation.sky
+++ /dev/null
@@ -1,36 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="/sky/framework/inspector/dom-agent.sky" as="DOMAgent" />
-<div><div></div></div>
-<script>
-// setTimeout to flush pending DOM modifications and measure
-// only the changes we want to.
-var expectedMessages = [
-    'DOM.childNodeRemoved',
-    'DOM.childNodeInserted',
-];
-var actualMessages = [];
-
-setTimeout(function() {
-    var delegate = {
-        sendMessage: function(message, params) {
-            actualMessages.push(message);
-        }
-    };
-
-    var domAgent = new DOMAgent(delegate);
-    domAgent.enable();
-
-    var adding = document.createElement('adding');
-    var container = document.querySelector('div');
-    container.firstChild.remove();
-    container.appendChild(document.createElement('adding'));
-
-    setTimeout(function() {
-        assert.equal(JSON.stringify(expectedMessages),
-            JSON.stringify(actualMessages));
-        internals.notifyTestComplete("Done!");
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/inspector/page-agent-get-resource-expected.txt b/engine/src/flutter/tests/inspector/page-agent-get-resource-expected.txt
deleted file mode 100644
index f96104a940..0000000000
--- a/engine/src/flutter/tests/inspector/page-agent-get-resource-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-Got message!
diff --git a/engine/src/flutter/tests/inspector/page-agent-get-resource-tree-expected.txt b/engine/src/flutter/tests/inspector/page-agent-get-resource-tree-expected.txt
deleted file mode 100644
index c00763c60a..0000000000
--- a/engine/src/flutter/tests/inspector/page-agent-get-resource-tree-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 PageAgent.getResourceTree should dump the current resource tree
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/inspector/page-agent-get-resource-tree.sky b/engine/src/flutter/tests/inspector/page-agent-get-resource-tree.sky
deleted file mode 100644
index 48c78f8a75..0000000000
--- a/engine/src/flutter/tests/inspector/page-agent-get-resource-tree.sky
+++ /dev/null
@@ -1,43 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<import src="/sky/framework/inspector/page-agent.sky" as="PageAgent" />
-<img src='does_not_exist.jpg' />
-<script>
-describe('PageAgent.getResourceTree', function() {
-  it('should dump the current resource tree', function() {
-    var pageAgent = new PageAgent();
-    pageAgent.enable();
-    var resourceTree = pageAgent.getResourceTree();
-    assert.deepEqual(resourceTree, {
-      "frameTree": {
-        "frame": {
-          "id": "1",
-          "loaderId": "1",
-          "url": "http://127.0.0.1:8000/sky/tests/inspector/page-agent-get-resource-tree.sky",
-          "mimeType": "text/html",
-          "securityOrigin": "http://127.0.0.1:8000/sky/tests/inspector/page-agent-get-resource-tree.sky"
-        },
-        "resources": [{
-          "url": "http://127.0.0.1:8000/sky/tests/resources/chai.sky",
-          "type": "Document",
-          "mimeType": "text/html"
-        }, {
-          "url": "http://127.0.0.1:8000/sky/tests/resources/mocha.sky",
-          "type": "Document",
-          "mimeType": "text/html"
-        }, {
-          "url": "http://127.0.0.1:8000/sky/framework/inspector/page-agent.sky",
-          "type": "Document",
-          "mimeType": "text/html"
-        }, {
-          "url": "http://127.0.0.1:8000/sky/tests/inspector/does_not_exist.jpg",
-          "type": "Image",
-          "mimeType": "image/unknown"
-        }]
-      }
-    });
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/js/classes-expected.txt b/engine/src/flutter/tests/js/classes-expected.txt
deleted file mode 100644
index 348fbc3cb6..0000000000
--- a/engine/src/flutter/tests/js/classes-expected.txt
+++ /dev/null
@@ -1,14 +0,0 @@
-Running 10 tests
-ok 1 ES6 classes should create instances
-ok 2 ES6 classes should create subclasses
-ok 3 ES6 classes should create anonymous classes
-ok 4 ES6 classes should put methods on the prototype
-ok 5 ES6 classes should call methods with |this|
-ok 6 ES6 classes should let toMethod rebind super
-ok 7 ES6 classes should support super() constructor calls
-ok 8 ES6 classes should automatically call super() in default constructor
-ok 9 ES6 classes should call super.method()
-ok 10 ES6 classes should support getters and setters
-10 tests
-10 pass
-0 fail
diff --git a/engine/src/flutter/tests/js/classes.sky b/engine/src/flutter/tests/js/classes.sky
deleted file mode 100644
index a8d09e272e..0000000000
--- a/engine/src/flutter/tests/js/classes.sky
+++ /dev/null
@@ -1,163 +0,0 @@
-<sky>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe("ES6 classes", function() {
-  it("should create instances", function() {
-    class Example {}
-    var instance = new Example();
-    assert.instanceOf(instance, Example);
-  });
-
-  it("should create subclasses", function() {
-    class Parent {}
-    class Child extends Parent {}
-    var instance = new Child();
-    assert.instanceOf(instance, Child);
-    assert.instanceOf(instance, Parent);
-  });
-
-  it("should create anonymous classes", function() {
-    var Parent = class {}
-    var Child = class extends Parent {}
-    var instance = new Child();
-    assert.instanceOf(instance, Child);
-    assert.instanceOf(instance, Parent);
-  });
-
-  it("should put methods on the prototype", function() {
-    class Test {
-      exampleMethod() { }
-    }
-    var instance = new Test();
-    assert.isFalse(instance.hasOwnProperty("exampleMethod"));
-    var proto = Object.getPrototypeOf(instance);
-    assert.isTrue(proto.hasOwnProperty("exampleMethod"));
-  });
-
-  it("should call methods with |this|", function() {
-    class Adder {
-      constructor(value) {
-        this.value = value;
-      }
-      add(other) {
-        return this.value + other;
-      }
-    }
-
-    var adder = new Adder(10);
-    assert.equal(adder.add(15), 25);
-  });
-
-  it("should let toMethod rebind super", function() {
-    var getValue = function() {
-      assert.isFunction(this.value);
-      assert.isFunction(this.superValue);
-      return this.value() + super.superValue();
-    }
-
-    class HolderParent {
-      superValue() {
-        return 5;
-      }
-    }
-
-    class Holder extends HolderParent {
-      constructor() {
-        this.value_ = 5;
-      }
-      value() {
-        return this.value_;
-      }
-    }
-
-    var holder = new Holder();
-    var getValueMethod = getValue.toMethod(Holder.prototype);
-    assert.equal(getValueMethod.call(holder), 10);
-  });
-
-  it("should support super() constructor calls", function() {
-    class Parent {
-      constructor(value) {
-        this.value = value;
-      }
-    }
-
-    class Child extends Parent {
-      constructor(value) {
-        super(value + 5);
-      }
-    }
-
-    var child = new Child(10);
-    assert.equal(child.value, 15);
-  });
-
-  it("should automatically call super() in default constructor", function() {
-    class Parent {
-      constructor() {
-        this.value = 10;
-      }
-    }
-
-    class Child extends Parent {
-    }
-
-    var child = new Child();
-    assert.equal(child.value, 10);
-  });
-
-  it("should call super.method()", function() {
-    class Parent {
-      value() {
-        return 10;
-      }
-    }
-
-    class Child extends Parent {
-      value() {
-        return super.value() + 5;
-      }
-    }
-
-    var child = new Child();
-    assert.equal(child.value(), 15);
-  });
-
-  it("should support getters and setters", function() {
-    class Variable {
-      constructor(value) {
-        this.value_ = value;
-      }
-
-      get value() {
-        return this.value_;
-      }
-
-      set value(newValue) {
-        this.value_ = newValue;
-      }
-    }
-
-    var variable = new Variable("first");
-
-    // Methods are on the prototype.
-    var proto = Object.getPrototypeOf(variable);
-    var descriptor = Object.getOwnPropertyDescriptor(proto, "value");
-    assert.isObject(descriptor);
-    assert.isFunction(descriptor.get);
-    assert.isFunction(descriptor.set);
-    assert.isUndefined(descriptor.value);
-
-    // Getter and setter should not be on the instance.
-    assert.isUndefined(Object.getOwnPropertyDescriptor(variable, "value"));
-
-    assert.equal(variable.value, "first");
-    assert.equal(variable.value_, "first");
-    variable.value = "second";
-    assert.equal(variable.value, "second");
-    assert.equal(variable.value_, "second");
-  });
-});
-</script>
-</sky>
diff --git a/engine/src/flutter/tests/mocha/describe-only-expected.txt b/engine/src/flutter/tests/mocha/describe-only-expected.txt
deleted file mode 100644
index 44a7b54fe1..0000000000
--- a/engine/src/flutter/tests/mocha/describe-only-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 This suite should run this test
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mocha/describe-only.sky b/engine/src/flutter/tests/mocha/describe-only.sky
deleted file mode 100644
index 62da377d81..0000000000
--- a/engine/src/flutter/tests/mocha/describe-only.sky
+++ /dev/null
@@ -1,20 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-
-describe.only('This suite', function() {
-  it('should run this test', function() {
-    assert.ok(true);
-  });
-});
-
-describe('That suite', function() {
-  it('should not run this test', function() {
-    assert.ok(false);
-  });
-});
-
-
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mocha/it-only-expected.txt b/engine/src/flutter/tests/mocha/it-only-expected.txt
deleted file mode 100644
index ff235c1562..0000000000
--- a/engine/src/flutter/tests/mocha/it-only-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 This suite should only run this test
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mocha/it-only.sky b/engine/src/flutter/tests/mocha/it-only.sky
deleted file mode 100644
index 616016a96b..0000000000
--- a/engine/src/flutter/tests/mocha/it-only.sky
+++ /dev/null
@@ -1,18 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-
-describe('This suite', function() {
-  it.only('should only run this test', function() {
-    assert.ok(true);
-  });
-
-  it('should not run this test', function() {
-    assert.ok(false);
-  });
-});
-
-
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/callback-arguments-expected.txt b/engine/src/flutter/tests/mutation-observer/callback-arguments-expected.txt
deleted file mode 100644
index b68fab40b7..0000000000
--- a/engine/src/flutter/tests/mutation-observer/callback-arguments-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver should pass the callback and observer arguments
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/callback-arguments.sky b/engine/src/flutter/tests/mutation-observer/callback-arguments.sky
deleted file mode 100644
index ea4a27266c..0000000000
--- a/engine/src/flutter/tests/mutation-observer/callback-arguments.sky
+++ /dev/null
@@ -1,18 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver', function() {
-    it('should pass the callback and observer arguments', function(done) {
-        var mutationObserver = new MutationObserver(function(mutations, observer) {
-            assert.equal(this, mutationObserver);
-            assert.equal(mutationObserver, observer);
-            done();
-        });
-        var div = document.createElement('div');
-        mutationObserver.observe(div, {attributes: true});
-        div.setAttribute('foo', 'bar');
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/clear-transient-without-delivery-expected.txt b/engine/src/flutter/tests/mutation-observer/clear-transient-without-delivery-expected.txt
deleted file mode 100644
index 606493102d..0000000000
--- a/engine/src/flutter/tests/mutation-observer/clear-transient-without-delivery-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 Transient registrations should be cleared even without delivery
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/clear-transient-without-delivery.sky b/engine/src/flutter/tests/mutation-observer/clear-transient-without-delivery.sky
deleted file mode 100644
index 60938dcb85..0000000000
--- a/engine/src/flutter/tests/mutation-observer/clear-transient-without-delivery.sky
+++ /dev/null
@@ -1,28 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('Transient registrations', function() {
-    it('should be cleared even without delivery', function(done) {
-        var mutationsDelivered = false;
-        var observer = new MutationObserver(function(mutations) {
-            mutationsDelivered = true;
-        });
-        var div = document.createElement('div');
-        var span = div.appendChild(document.createElement('span'));
-        observer.observe(div, {attributes: true, subtree: true});
-        div.removeChild(span);
-        setTimeout(function() {
-            // By the time this function runs the transient registration should
-            // be cleared, so we expect not to be notified of this attribute
-            // mutation.
-            span.setAttribute('bar', 'baz');
-            setTimeout(function() {
-                assert.notOk(mutationsDelivered);
-                done();
-            }, 0);
-        }, 0);
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/create-during-delivery-expected.txt b/engine/src/flutter/tests/mutation-observer/create-during-delivery-expected.txt
deleted file mode 100644
index 8850360a1e..0000000000
--- a/engine/src/flutter/tests/mutation-observer/create-during-delivery-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObservers must wait for the next loop when created during delivery
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/create-during-delivery.sky b/engine/src/flutter/tests/mutation-observer/create-during-delivery.sky
deleted file mode 100644
index 40158e24f1..0000000000
--- a/engine/src/flutter/tests/mutation-observer/create-during-delivery.sky
+++ /dev/null
@@ -1,37 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-window.jsTestIsAsync = true;
-
-describe('MutationObservers', function() {
-    it ('must wait for the next loop when created during delivery', function(done) {
-        var order = [];
-        var div = document.createElement('div');
-
-        var observer3;
-        var observer1 = new MutationObserver(function(mutations) {
-            order.push(1);
-            if (!observer3) {
-                observer3 = new MutationObserver(function(mutations) {
-                    order.push(3);
-                });
-                observer3.observe(div, {attributes: true});
-                div.setAttribute('foo', 'baz');
-            }
-        });
-        var observer2 = new MutationObserver(function(mutations) {
-            order.push(2);
-        });
-
-        observer1.observe(div, {attributes: true});
-        observer2.observe(div, {attributes: true});
-        div.setAttribute('foo', 'bar');
-        setTimeout(function() {
-            assert.deepEqual(order, [1, 2, 1, 3]);
-            done();
-        }, 0);
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/cross-document-expected.txt b/engine/src/flutter/tests/mutation-observer/cross-document-expected.txt
deleted file mode 100644
index f9addc732a..0000000000
--- a/engine/src/flutter/tests/mutation-observer/cross-document-expected.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-Running 2 tests
-ok 1 MutationObserver cross document moves should handle basic observation
-ok 2 MutationObserver cross document moves should handle subtree observation
-2 tests
-2 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/cross-document.sky b/engine/src/flutter/tests/mutation-observer/cross-document.sky
deleted file mode 100644
index fdf93efc53..0000000000
--- a/engine/src/flutter/tests/mutation-observer/cross-document.sky
+++ /dev/null
@@ -1,49 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver cross document moves', function() {
-    it('should handle basic observation', function(done) {
-        var mutations;
-        var div = document.createElement('div');
-        var observer = new MutationObserver(function(records) {
-            mutations = records;
-        });
-
-        observer.observe(div, {attributes: true});
-        var newDoc = new Document();
-        newDoc.appendChild(div);
-        div.id = 'foo';
-        setTimeout(function() {
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].type, 'attributes');
-            assert.equal(mutations[0].target, div);
-            assert.equal(mutations[0].attributeName, 'id');
-            observer.disconnect();
-            done();
-        }, 0);
-    });
-    it('should handle subtree observation', function(done) {
-        var mutations;
-        var div = document.createElement('div');
-        var subDiv = div.appendChild(document.createElement('div'));
-        var observer = new MutationObserver(function(records) {
-            mutations = records;
-        });
-
-        observer.observe(div, {attributes: true, subtree: true});
-        var newDoc = new Document();
-        newDoc.appendChild(div);
-        subDiv.id = 'foo';
-        setTimeout(function() {
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].type, 'attributes');
-            assert.equal(mutations[0].target, subDiv);
-            assert.equal(mutations[0].attributeName, 'id');
-            observer.disconnect();
-            done();
-        }, 0);
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/delivery-order-expected.txt b/engine/src/flutter/tests/mutation-observer/delivery-order-expected.txt
deleted file mode 100644
index 53bcfce41f..0000000000
--- a/engine/src/flutter/tests/mutation-observer/delivery-order-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver should deliver in order of creation
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/delivery-order.sky b/engine/src/flutter/tests/mutation-observer/delivery-order.sky
deleted file mode 100644
index bf056d1aa2..0000000000
--- a/engine/src/flutter/tests/mutation-observer/delivery-order.sky
+++ /dev/null
@@ -1,40 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver', function() {
-    it('should deliver in order of creation', function(done) {
-        var order = [];
-        var observers = [];
-
-        function setUpOrdering(num) {
-            observers.push(new MutationObserver(function(mutations) {
-                order.push(num);
-            }));
-        }
-
-        for (var i = 0; i < 10; ++i)
-            setUpOrdering(i);
-
-        var div = document.createElement('div');
-        observers[3].observe(div, {attributes: true});
-        observers[2].observe(div, {characterData: true, subtree: true});
-        observers[1].observe(div, {attributes: true});
-        observers[7].observe(div, {childList: true});
-        observers[4].observe(div, {attributes: true});
-        observers[9].observe(div, {attributes: true});
-        observers[0].observe(div, {childList: true});
-        observers[5].observe(div, {attributes: true});
-        observers[6].observe(div, {characterData: true, subtree: true});
-        observers[8].observe(div, {attributes: true});
-        div.setAttribute('foo', 'bar');
-        div.appendChild(new Text('hello'));
-        div.firstChild.textContent = 'goodbye';
-        setTimeout(function() {
-            assert.deepEqual(order, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]);
-            done();
-        }, 0);
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/disconnect-cancel-pending-expected.txt b/engine/src/flutter/tests/mutation-observer/disconnect-cancel-pending-expected.txt
deleted file mode 100644
index f87992fda2..0000000000
--- a/engine/src/flutter/tests/mutation-observer/disconnect-cancel-pending-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver.disconnect should cancel pending delivery
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/disconnect-cancel-pending.sky b/engine/src/flutter/tests/mutation-observer/disconnect-cancel-pending.sky
deleted file mode 100644
index 83cab7c17e..0000000000
--- a/engine/src/flutter/tests/mutation-observer/disconnect-cancel-pending.sky
+++ /dev/null
@@ -1,44 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver.disconnect', function() {
-    it('should cancel pending delivery', function(done) {
-        var mutations;
-        var observer;
-        var div;
-
-        function start() {
-            mutations = null;
-            div = document.createElement('div');
-
-            observer = new MutationObserver(function(m) {
-                mutations = m;
-            });
-
-            observer.observe(div, { attributes: true });
-            div.setAttribute('foo', 'bar');
-            observer.disconnect();
-            setTimeout(next, 0);
-        }
-
-        function next() {
-            // Disconnecting should cancel any pending delivery...
-            assert.equal(mutations, null);
-            observer.observe(div, { attributes: true });
-            div.setAttribute('bar', 'baz');
-            setTimeout(finish, 0);
-        }
-
-        function finish() {
-            // ...and re-observing should not see any of the previously-generated records.
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].attributeName, "bar");
-            done();
-        }
-
-        start();
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/document-fragment-insertion-expected.txt b/engine/src/flutter/tests/mutation-observer/document-fragment-insertion-expected.txt
deleted file mode 100644
index dd23333a41..0000000000
--- a/engine/src/flutter/tests/mutation-observer/document-fragment-insertion-expected.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-Running 3 tests
-ok 1 DocumentFragments should remove all children of the fragment before moving children, using appendChild
-ok 2 DocumentFragments should remove all children of the fragment before moving children, using insertBefore
-ok 3 DocumentFragments should remove all children of the fragment before moving children, using replaceChild
-3 tests
-3 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/document-fragment-insertion.sky b/engine/src/flutter/tests/mutation-observer/document-fragment-insertion.sky
deleted file mode 100644
index ddaff1c110..0000000000
--- a/engine/src/flutter/tests/mutation-observer/document-fragment-insertion.sky
+++ /dev/null
@@ -1,69 +0,0 @@
-<html>
-<import src="../resources/mocha.sky" />
-<import src="../resources/chai.sky" />
-<script>
-describe('DocumentFragments should remove all children of the fragment before moving children, ', function() {
-  var mutations;
-  var observer;
-
-  beforeEach(function() {
-    mutations = null;
-    observer = new MutationObserver(function(records) {
-      mutations = records;
-    });
-  });
-
-  function createObservedFragment() {
-    var fragment = document.createDocumentFragment();
-    fragment.appendChild(document.createElement('b'));
-    fragment.appendChild(document.createElement('i'));
-    observer.observe(fragment, {childList: true});
-    return fragment;
-  }
-
-  it('using appendChild', function(done) {
-    var div = document.createElement('div');
-    observer.observe(div, {childList: true});
-    div.appendChild(createObservedFragment());
-    setTimeout(function() {
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].addedNodes.length, 0);
-      assert.equal(mutations[0].removedNodes.length, 2);
-      assert.equal(mutations[1].addedNodes.length, 2);
-      assert.equal(mutations[1].removedNodes.length, 0);
-      done();
-    }, 0);
-  });
-
-  it('using insertBefore', function(done) {
-    var div = document.createElement('div');
-    div.appendChild(document.createElement('span'));
-    observer.observe(div, {childList: true});
-    div.insertBefore(createObservedFragment(), div.firstChild);
-    setTimeout(function() {
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].addedNodes.length, 0);
-      assert.equal(mutations[0].removedNodes.length, 2);
-      assert.equal(mutations[1].addedNodes.length, 2);
-      assert.equal(mutations[1].removedNodes.length, 0);
-      done();
-    }, 0);
-  });
-
-  it('using replaceChild', function(done) {
-    var div = document.createElement('div');
-    div.appendChild(document.createElement('span'));
-    observer.observe(div, {childList: true});
-    div.replaceChild(createObservedFragment(), div.firstChild);
-    setTimeout(function() {
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].addedNodes.length, 0);
-      assert.equal(mutations[0].removedNodes.length, 2);
-      assert.equal(mutations[1].addedNodes.length, 2);
-      assert.equal(mutations[1].removedNodes.length, 1);
-      done();
-    }, 0);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/mutate-during-delivery-expected.txt b/engine/src/flutter/tests/mutation-observer/mutate-during-delivery-expected.txt
deleted file mode 100644
index 2cd9842328..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutate-during-delivery-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver should not interrupt delivery order on getting mutations during delivery
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/mutate-during-delivery.sky b/engine/src/flutter/tests/mutation-observer/mutate-during-delivery.sky
deleted file mode 100644
index 41ec4c787e..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutate-during-delivery.sky
+++ /dev/null
@@ -1,34 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver', function() {
-  it('should not interrupt delivery order on getting mutations during delivery', function(done) {
-    function finish() {
-      assert.deepEqual(order, [1, 3, 2]);
-      done();
-    }
-
-    var order = [];
-    var div = document.createElement('div');
-
-    var observer1 = new MutationObserver(function(mutations) {
-      order.push(1);
-      div.appendChild(document.createElement('span'));
-    });
-    var observer2 = new MutationObserver(function(mutations) {
-      order.push(2);
-    });
-    var observer3 = new MutationObserver(function(mutations) {
-      order.push(3);
-    });
-
-    observer1.observe(div, {attributes: true});
-    observer2.observe(div, {childList: true});
-    observer3.observe(div, {attributes: true});
-    div.setAttribute('foo', 'bar');
-    setTimeout(finish, 0);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-callback-non-element-crash-expected.txt b/engine/src/flutter/tests/mutation-observer/mutation-callback-non-element-crash-expected.txt
deleted file mode 100644
index bc057cbdff..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-callback-non-element-crash-expected.txt
+++ /dev/null
@@ -1 +0,0 @@
-PASS. We didn't crash
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-callback-non-element-crash.sky b/engine/src/flutter/tests/mutation-observer/mutation-callback-non-element-crash.sky
deleted file mode 100644
index 89450e7fb1..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-callback-non-element-crash.sky
+++ /dev/null
@@ -1,15 +0,0 @@
-<html>
-<import src="../resources/dump-as-text.sky" />
-<body id="body">
-<script>
-function mutationCallback(mutations, observer) {
-    mutations[0].addedNodes[-1];
-}
-
-var mutationObserver = new MutationObserver(mutationCallback);
-var body = document.getElementById("body");
-mutationObserver.observe(body, {childList: true});
-body.appendChild(new Text("PASS. We didn't crash"));
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-observer-constructor-expected.txt b/engine/src/flutter/tests/mutation-observer/mutation-observer-constructor-expected.txt
deleted file mode 100644
index 3a84b311af..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-observer-constructor-expected.txt
+++ /dev/null
@@ -1,6 +0,0 @@
-Running 2 tests
-ok 1 MutationObserver should have methods
-ok 2 MutationObserver should throw with incorrect constructor args
-2 tests
-2 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-observer-constructor.sky b/engine/src/flutter/tests/mutation-observer/mutation-observer-constructor.sky
deleted file mode 100644
index ce6749a575..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-observer-constructor.sky
+++ /dev/null
@@ -1,28 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver', function() {
-    var observer = new MutationObserver(function(mutations) { });
-
-    it('should have methods', function() {
-        assert.equal(typeof observer.observe, 'function');
-        assert.equal(typeof observer.disconnect, 'function');
-    });
-    it('should throw with incorrect constructor args', function() {
-        assert.throw(function() {
-            new MutationObserver({ handleEvent: function() {} });
-        }, TypeError);
-        assert.throw(function() {
-            new MutationObserver({});
-        }, TypeError);
-        assert.throw(function() {
-            new MutationObserver(42);
-        }, TypeError);
-        assert.throw(function() {
-            new MutationObserver("foo");
-        }, TypeError);
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-record-constructor-expected.txt b/engine/src/flutter/tests/mutation-observer/mutation-record-constructor-expected.txt
deleted file mode 100644
index 5676f7c77c..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-record-constructor-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationRecord should be exposed on window but not constructable
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-record-constructor.sky b/engine/src/flutter/tests/mutation-observer/mutation-record-constructor.sky
deleted file mode 100644
index 2c1d9de58f..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-record-constructor.sky
+++ /dev/null
@@ -1,22 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationRecord', function() {
-  it('should be exposed on window but not constructable', function() {
-    assert.ok(window.MutationRecord);
-    assert.equal(typeof MutationRecord, "function");
-    assert.throw(function() {
-        new MutationRecord
-    }, TypeError);
-
-    var div = document.createElement('div');
-    var observer = new MutationObserver(function(){});
-    observer.observe(div, {attributes: true});
-    div.id = 'foo';
-    var record = observer.takeRecords()[0];
-    assert.ok(record instanceof MutationRecord);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-record-nullity-expected.txt b/engine/src/flutter/tests/mutation-observer/mutation-record-nullity-expected.txt
deleted file mode 100644
index a972d009b2..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-record-nullity-expected.txt
+++ /dev/null
@@ -1,7 +0,0 @@
-Running 3 tests
-ok 1 Non-relevant properties on mutation records should be null, except for NodeLists, which should be empty on characterData records
-ok 2 Non-relevant properties on mutation records should be null, except for NodeLists, which should be empty on childList records
-ok 3 Non-relevant properties on mutation records should be null, except for NodeLists, which should be empty on attribute records
-3 tests
-3 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/mutation-record-nullity.sky b/engine/src/flutter/tests/mutation-observer/mutation-record-nullity.sky
deleted file mode 100644
index a3dfe00380..0000000000
--- a/engine/src/flutter/tests/mutation-observer/mutation-record-nullity.sky
+++ /dev/null
@@ -1,42 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('Non-relevant properties on mutation records should be null, except for NodeLists, which should be empty', function() {
-
-  var observer = new MutationObserver(function() {});
-
-  it('on characterData records', function() {
-    var text = new Text('something');
-    observer.observe(text, {characterData: true});
-    text.data = 'something else';
-    var record = observer.takeRecords()[0];
-    assert.isNull(record.attributeName);
-    assert.isNull(record.oldValue);
-    assert.isNull(record.previousSibling);
-    assert.isNull(record.nextSibling);
-    assert.equal(record.addedNodes.length, 0);
-    assert.equal(record.removedNodes.length, 0);
-  });
-  it('on childList records', function() {
-    var div = document.createElement('div');
-    observer.observe(div, {childList: true});
-    div.appendChild(document.createElement('span'));
-    var record = observer.takeRecords()[0];
-    assert.isNull(record.attributeName);
-    assert.isNull(record.oldValue);
-  });
-  it('on attribute records', function() {
-    var div = document.createElement('div');
-    observer.observe(div, {attributes: true});
-    div.setAttribute('data-foo', 'bar');
-    var record = observer.takeRecords()[0];
-    assert.isNull(record.oldValue);
-    assert.isNull(record.previousSibling);
-    assert.isNull(record.nextSibling);
-    assert.equal(record.addedNodes.length, 0);
-    assert.equal(record.removedNodes.length, 0);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-attributes-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-attributes-expected.txt
deleted file mode 100644
index 1762a1ad67..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-attributes-expected.txt
+++ /dev/null
@@ -1,20 +0,0 @@
-ERROR: Failed to load resource: the server responded with a status of 404 () 
-SOURCE: http://127.0.0.1:8000/sky/tests/mutation-observer/baz.png:0
-Running 14 tests
-ok 1 MutationObserver.observe on attributes should handle basic aspects of attribute observation
-ok 2 MutationObserver.observe on attributes should not notify of attribute changes without asking
-ok 3 MutationObserver.observe on attributes re-observing the same node with the same observer has the effect of resetting the options
-ok 4 MutationObserver.observe on attributes multiple observers can be registered to a given node and both receive mutations
-ok 5 MutationObserver.observe on attributes should deliver mutations on modifications to node properties which delegate to attribute storage
-ok 6 MutationObserver.observe on attributes should handle basic oldValue delivery
-ok 7 MutationObserver.observe on attributes should deliver oldValue when needed
-ok 8 MutationObserver.observe on attributes should give attributeOldValue if any entries request it with multiple observers
-ok 9 MutationObserver.observe on attributes should handle setting an attribute via reflected IDL attribute
-ok 10 MutationObserver.observe on attributes should respect attributeFilter on HTML elements
-ok 11 MutationObserver.observe on attributes should respect different attributeFilters when observing multiple subtree nodes
-ok 12 MutationObserver.observe on attributes should create records for the style property
-ok 13 MutationObserver.observe on attributes should have oldValue for style property mutations
-ok 14 MutationObserver.observe on attributes should not create records for noop style property mutation
-14 tests
-14 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-attributes.sky b/engine/src/flutter/tests/mutation-observer/observe-attributes.sky
deleted file mode 100644
index c824351fc7..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-attributes.sky
+++ /dev/null
@@ -1,569 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver.observe on attributes', function() {
-  it('should handle basic aspects of attribute observation', function(done) {
-    var div;
-    var observer;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      div.setAttribute('bar', 'foo');
-
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      observer.observe(div, { attributes: true, characterData: true });
-      div.setAttribute('foo', 'bar');
-      div.removeAttribute('bar');
-      setTimeout(checkDisconnectAndMutate, 0);
-    }
-
-    function checkDisconnectAndMutate() {
-      // ...can attribute changes be observed at all
-
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "bar");
-
-      mutations = null;
-      observer.disconnect();
-      div.setAttribute('foo', 'baz');
-      setTimeout(checkNotDeliveredAndMutateMultiple, 0);
-    }
-
-    function checkNotDeliveredAndMutateMultiple() {
-      // ...observer.disconnect() should prevent further delivery of mutations.
-
-      assert.equal(mutations, null);
-      observer.observe(div, { attributes: true });
-      div.setAttribute('foo', 'bat');
-      div.setAttribute('bar', 'foo');
-      setTimeout(finish);
-    }
-
-    function finish() {
-      // ...re-observing after disconnect works with the same observer.
-
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "bar");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should not notify of attribute changes without asking', function(done) {
-    var div;
-    var observer;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      observer.observe(div, { childList: true, characterData: true });
-      div.setAttribute('foo', 'bar');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations, null);
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('re-observing the same node with the same observer has the effect of resetting the options', function(done) {
-    var div;
-    var observer;
-    var mutations;
-    var calls = 0;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-        calls++;
-      });
-
-      observer.observe(div, { attributes: true, characterData: true });
-      observer.observe(div, { attributes: true });
-      div.setAttribute('foo', 'bar');
-      setTimeout(checkDisconnectAndMutate, 0);
-    }
-
-    function checkDisconnectAndMutate() {
-      assert.equal(calls, 1);
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      mutations = null;
-      observer.observe(div, { attributes: true, characterData: true });
-      observer.observe(div, { childList: true });
-      div.setAttribute('foo', 'baz');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations, null);
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('multiple observers can be registered to a given node and both receive mutations', function(done) {
-    var div;
-    var observer;
-    var observer2;
-    var mutations;
-    var mutations2;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-      observer2 = new MutationObserver(function(records) {
-        mutations2 = records;
-      });
-      observer.observe(div, { attributes: true });
-      observer2.observe(div, { attributes: true });
-      div.setAttribute('foo', 'bar');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations2.length, 1);
-      assert.equal(mutations2[0].type, "attributes");
-      assert.equal(mutations2[0].attributeName, "foo");
-      observer.disconnect();
-      observer2.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should deliver mutations on modifications to node properties which delegate to attribute storage', function(done) {
-    var img, a;
-    var observer;
-    var mutations;
-
-    function start() {
-      img = document.createElement('img');
-      a = document.createElement('a');
-
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      observer.observe(img, { attributes: true });
-      observer.observe(a, { attributes: true });
-
-      img.src = 'baz.png';
-      a.href = 'foo.html';
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "src");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "href");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle basic oldValue delivery', function(done) {
-    var div;
-    var observer;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      div.setAttribute('bar', 'boo');
-
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-      observer.observe(div, { attributes: true, attributeOldValue: true });
-      div.setAttribute('foo', 'bar');
-      div.setAttribute('foo', 'baz');
-      div.removeAttribute('bar');
-      div.removeAttribute('non-existant');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 3);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[0].oldValue, null);
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "foo");
-      assert.equal(mutations[1].oldValue, "bar");
-      assert.equal(mutations[2].type, "attributes");
-      assert.equal(mutations[2].attributeName, "bar");
-      assert.equal(mutations[2].oldValue, "boo");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should deliver oldValue when needed', function(done) {
-    var div;
-    var observerWithOldValue;
-    var observer;
-    var mutationsWithOldValue;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      div.setAttribute('foo', 'bar');
-      observerWithOldValue = new MutationObserver(function(records) {
-        mutationsWithOldValue = records;
-      });
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-      observerWithOldValue.observe(div, { attributes: true, attributeOldValue: true });
-      observer.observe(div, { attributes: true });
-      div.setAttribute('foo', 'baz');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutationsWithOldValue.length, 1);
-      assert.equal(mutationsWithOldValue[0].type, "attributes");
-      assert.equal(mutationsWithOldValue[0].attributeName, "foo");
-      assert.equal(mutationsWithOldValue[0].oldValue, "bar");
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[0].oldValue, null);
-      observerWithOldValue.disconnect();
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should give attributeOldValue if any entries request it with multiple observers', function(done) {
-    var div;
-    var span;
-    var observer;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      span = div.appendChild(document.createElement('span'));
-      span.setAttribute('foo', 'bar');
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-      observer.observe(div, { attributes: true, attributeOldValue: true, subtree: true });
-      observer.observe(span, { attributes: true });
-      span.setAttribute('foo', 'baz');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[0].oldValue, "bar");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle setting an attribute via reflected IDL attribute', function(done) {
-    var div;
-    var observer;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-      observer.observe(div, { attributes: true, attributeOldValue: true });
-      div.id = 'foo';
-      div.id = 'bar';
-      div.id = null;
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 3);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "id");
-      assert.equal(mutations[0].oldValue, null);
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "id");
-      assert.equal(mutations[1].oldValue, "foo");
-      assert.equal(mutations[2].type, "attributes");
-      assert.equal(mutations[2].attributeName, "id");
-      assert.equal(mutations[2].oldValue, "bar");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should respect attributeFilter on HTML elements', function(done) {
-    var div, path;
-    var observer;
-    var mutations;
-
-    function start() {
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      div = document.createElement('div');
-      observer.observe(div, { attributes: true, attributeFilter: ['foo', 'bar', 'booM'] });
-      div.setAttribute('foo', 'foo');
-      div.setAttribute('bar', 'bar');
-      div.setAttribute('baz', 'baz');
-      div.setAttribute('BOOm', 'boom');
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...only foo and bar should be received.
-
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "bar");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should respect different attributeFilters when observing multiple subtree nodes', function(done) {
-    var div, div2, div3;
-    var observer;
-    var mutations;
-
-    function start() {
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      div = document.createElement('div');
-      div2 = div.appendChild(document.createElement('div'));
-      div3 = div2.appendChild(document.createElement('div'));
-
-      observer.observe(div, { attributes: true, subtree: true, attributeFilter: ['foo', 'bar'] });
-      observer.observe(div2, { attributes: true, subtree: true, attributeFilter: ['bar', 'bat'] });
-
-      div3.setAttribute('foo', 'foo');
-      div3.setAttribute('bar', 'bar');
-      div3.setAttribute('bat', 'bat');
-      div3.setAttribute('baz', 'baz');
-
-      setTimeout(checkAndObserveAll, 0);
-    }
-
-    function checkAndObserveAll() {
-      // ...only foo, bar & bat should be received.
-
-      assert.equal(mutations.length, 3);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "bar");
-      assert.equal(mutations[2].type, "attributes");
-      assert.equal(mutations[2].attributeName, "bat");
-
-      observer.observe(div2, { attributes: true, subtree: true });
-      div3.setAttribute('bar', 'bar');
-      div3.setAttribute('bat', 'bat');
-      div3.setAttribute('baz', 'baz');
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...bar, bat & baz should all be received.
-
-      assert.equal(mutations.length, 3);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "bar");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "bat");
-      assert.equal(mutations[2].type, "attributes");
-      assert.equal(mutations[2].attributeName, "baz");
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should create records for the style property', function(done) {
-    var div, path;
-    var observer;
-    var mutations;
-
-    function start() {
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      div = document.createElement('div');
-      div.setAttribute('style', 'color: yellow; width: 100px;');
-      observer.observe(div, { attributes: true });
-      div.style.color = 'red';
-      div.style.width = '200px';
-      div.style.color = 'blue';
-
-      setTimeout(checkAndContinue, 0);
-    }
-
-    function checkAndContinue() {
-      assert.equal(mutations.length, 3);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "style");
-      assert.equal(mutations[0].oldValue, null);
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "style");
-      assert.equal(mutations[1].oldValue, null);
-      assert.equal(mutations[2].type, "attributes");
-      assert.equal(mutations[2].attributeName, "style");
-      assert.equal(mutations[2].oldValue, null);
-
-      mutations = null;
-      div.getAttribute('style');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...mutation record created.
-
-      assert.equal(mutations, null);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should have oldValue for style property mutations', function(done) {
-    var div, path;
-    var observer;
-    var mutations;
-
-    function start() {
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      div = document.createElement('div');
-      div.setAttribute('style', 'color: yellow; width: 100px;');
-      observer.observe(div, { attributes: true, attributeOldValue: true });
-      div.style.color = 'red';
-      div.style.width = '200px';
-      div.style.color = 'blue';
-
-      setTimeout(checkAndContinue, 0);
-    }
-
-    function checkAndContinue() {
-      assert.equal(mutations.length, 3);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].attributeName, "style");
-      assert.equal(mutations[0].oldValue, "color: yellow; width: 100px;");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].attributeName, "style");
-      assert.equal(mutations[1].oldValue, "color: rgb(255, 0, 0); width: 100px;");
-      assert.equal(mutations[2].type, "attributes");
-      assert.equal(mutations[2].attributeName, "style");
-      assert.equal(mutations[2].oldValue, "color: rgb(255, 0, 0); width: 200px;");
-
-      mutations = null;
-      div.getAttribute('style');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...mutation record created.
-
-      assert.equal(mutations, null);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should not create records for noop style property mutation', function(done) {
-    var div, path;
-    var observer;
-    var mutations;
-
-    function start() {
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      div = document.createElement('div');
-      div.setAttribute('style', 'color: yellow; width: 100px;');
-      observer.observe(div, { attributes: true });
-      div.style.removeProperty('height');
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations, null);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-});
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-characterdata-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-characterdata-expected.txt
deleted file mode 100644
index 6edd60abb8..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-characterdata-expected.txt
+++ /dev/null
@@ -1,10 +0,0 @@
-Running 6 tests
-ok 1 MutationObserver on character data should handle basic aspects of characterData observation
-ok 2 MutationObserver on character data should only notify of characterData changes when requested
-ok 3 MutationObserver on character data should allow multiple observers can be registered to a given node and both receive mutations
-ok 4 MutationObserver on character data should provide oldValue is returned when requested
-ok 5 MutationObserver on character data should allow observing both with and without oldValue
-ok 6 MutationObserver on character data should provide oldValue if any observation requests it
-6 tests
-6 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-characterdata.sky b/engine/src/flutter/tests/mutation-observer/observe-characterdata.sky
deleted file mode 100644
index df264d94bc..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-characterdata.sky
+++ /dev/null
@@ -1,229 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<body id="body">
-<script>
-document.body = document.getElementById("body");
-
-describe('MutationObserver on character data', function() {
-    it('should handle basic aspects of characterData observation', function(done) {
-        var observer;
-        var mutations;
-        var charDataNode;
-
-        function start() {
-            var div = document.createElement('div');
-            div.textContent = 'foo';
-            charDataNode = div.firstChild;
-            observer = new MutationObserver(function(records) {
-                mutations = records;
-            });
-
-            observer.observe(charDataNode, {characterData: true});
-            charDataNode.textContent = 'bar';
-            setTimeout(checkDisconnectAndMutate, 0);
-        }
-
-        function checkDisconnectAndMutate() {
-            // ...can characterData changes be observed at all
-
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].type, "characterData");
-            assert.equal(mutations[0].target, charDataNode);
-
-            mutations = null;
-            observer.disconnect();
-            charDataNode.textContent = 'baz';
-            setTimeout(checkNotDeliveredAndMutateMultiple, 0);
-        }
-
-        function checkNotDeliveredAndMutateMultiple() {
-            // ...observer.disconnect() should prevent further delivery of mutations.
-
-            assert.equal(mutations, null);
-            charDataNode = new Text('');
-            observer.observe(charDataNode, { characterData: true });
-            charDataNode.textContent = 'foo';
-            charDataNode.textContent = 'bar';
-            setTimeout(finish);
-        }
-
-        function finish() {
-            // ...re-observing after disconnect works with the same observer.
-
-            assert.equal(mutations.length, 2);
-            assert.equal(mutations[0].type, "characterData");
-            assert.equal(mutations[0].target, charDataNode);
-            assert.equal(mutations[1].type, "characterData");
-            assert.equal(mutations[1].target, charDataNode);
-            observer.disconnect();
-            done();
-        }
-
-        start();
-    });
-
-    it('should only notify of characterData changes when requested', function(done) {
-        var observer;
-        var mutations;
-
-        function start() {
-            var div = document.createElement('div');
-            div.textContent = 'hello';
-            var charDataNode = div.firstChild;
-            observer = new MutationObserver(function(records) {
-                mutations = records;
-            });
-
-            observer.observe(charDataNode, {childList: true, attributes: true});
-            charDataNode = 'goodbye';
-            setTimeout(finish, 0);
-        }
-
-        function finish() {
-            assert.equal(mutations, null);
-            observer.disconnect();
-            done();
-        }
-
-        start();
-    });
-
-    it('should allow multiple observers can be registered to a given node and both receive mutations', function(done) {
-        var observer;
-        var observer2;
-        var charDataNode;
-        var mutations;
-        var mutations2;
-
-        function start() {
-            var div = document.createElement('div');
-            div.textContent = 'foo';
-            charDataNode = div.firstChild;
-            observer = new MutationObserver(function(records) {
-                mutations = records;
-            });
-            observer2 = new MutationObserver(function(records) {
-                mutations2 = records;
-            });
-            observer.observe(charDataNode, {characterData: true});
-            observer2.observe(charDataNode, {characterData: true});
-            charDataNode.textContent = 'bar';
-            setTimeout(finish, 0);
-        }
-
-        function finish() {
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].type, "characterData");
-            assert.equal(mutations[0].target, charDataNode);
-            assert.equal(mutations2.length, 1);
-            assert.equal(mutations2[0].type, "characterData");
-            assert.equal(mutations2[0].target, charDataNode);
-            observer.disconnect();
-            observer2.disconnect();
-            done();
-        }
-
-        start();
-    });
-
-    it('should provide oldValue is returned when requested', function(done) {
-        var observer;
-        var mutations;
-        var charDataNode;
-
-        function start() {
-            var div = document.createElement('div');
-            div.textContent = 'foo';
-            charDataNode = div.firstChild;
-            observer = new MutationObserver(function(records) {
-                mutations = records;
-            });
-            observer.observe(charDataNode, {characterData: true, characterDataOldValue: true});
-            charDataNode.textContent = 'bar';
-            charDataNode.textContent = 'baz';
-            setTimeout(finish, 0);
-        }
-
-        function finish() {
-            assert.equal(mutations.length, 2);
-            assert.equal(mutations[0].type, "characterData");
-            assert.equal(mutations[0].target, charDataNode);
-            assert.equal(mutations[0].oldValue, "foo");
-            assert.equal(mutations[1].type, "characterData");
-            assert.equal(mutations[1].target, charDataNode);
-            assert.equal(mutations[1].oldValue, "bar");
-            observer.disconnect();
-            done();
-        }
-
-        start();
-    });
-
-    it('should allow observing both with and without oldValue', function(done) {
-        var observerWithOldValue;
-        var observer;
-        var mutations;
-        var mutationsWithOldValue;
-
-        function start() {
-            var div = document.createElement('div');
-            div.textContent = 'foo';
-            var charDataNode = div.firstChild;
-            observerWithOldValue = new MutationObserver(function(records) {
-                mutationsWithOldValue = records;
-            });
-            observer = new MutationObserver(function(records) {
-                mutations = records;
-            });
-            observerWithOldValue.observe(charDataNode, {characterData: true, characterDataOldValue: true});
-            observer.observe(charDataNode, {characterData: true});
-            charDataNode.textContent = 'bar';
-            setTimeout(finish, 0);
-        }
-
-        function finish() {
-            assert.equal(mutationsWithOldValue.length, 1);
-            assert.equal(mutationsWithOldValue[0].type, "characterData");
-            assert.equal(mutationsWithOldValue[0].oldValue, "foo");
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].type, "characterData");
-            assert.equal(mutations[0].oldValue, null);
-            observerWithOldValue.disconnect();
-            observer.disconnect();
-            done();
-        }
-
-        start();
-    });
-
-    it('should provide oldValue if any observation requests it', function(done) {
-        var observer;
-        var mutations;
-
-        function start() {
-            var div = document.createElement('div');
-            div.textContent = 'foo';
-            var charDataNode = div.firstChild;
-            observer = new MutationObserver(function(records) {
-                mutations = records;
-            });
-            observer.observe(div, {characterData: true, characterDataOldValue: true, subtree: true});
-            observer.observe(charDataNode, {characterData: true});
-            charDataNode.textContent = 'bar';
-            setTimeout(finish, 0);
-        }
-
-        function finish() {
-            assert.equal(mutations.length, 1);
-            assert.equal(mutations[0].type, "characterData");
-            assert.equal(mutations[0].oldValue, "foo");
-            observer.disconnect();
-            done();
-        }
-
-        start();
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-childList-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-childList-expected.txt
deleted file mode 100644
index ad35d53d38..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-childList-expected.txt
+++ /dev/null
@@ -1,11 +0,0 @@
-Running 7 tests
-ok 1 MutationObserver.observe on childList should handle basic observation
-ok 2 MutationObserver.observe on childList should handle observing without specifying "childList" does not result in hearing about childList changes
-ok 3 MutationObserver.observe on childList should handle re-observing the same node with the same observer has the effect of resetting the options
-ok 4 MutationObserver.observe on childList should handle multiple observers can be registered to a given node and both receive mutations
-ok 5 MutationObserver.observe on childList should create minimal mutations for replaceChild
-ok 6 MutationObserver.observe on childList should create minimal mutations for insertBefore
-ok 7 MutationObserver.observe on childList should create minimal mutations for appendChild
-7 tests
-7 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-childList.sky b/engine/src/flutter/tests/mutation-observer/observe-childList.sky
deleted file mode 100644
index 63b8532114..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-childList.sky
+++ /dev/null
@@ -1,322 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver.observe on childList', function() {
-  it('should handle basic observation', function(done) {
-    var div;
-    var observer;
-    var mutations;
-    var removedDiv1, removedDiv2;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-      });
-
-      observer.observe(div, { childList: true });
-      removedDiv1 = div.appendChild(document.createElement('div'));
-      setTimeout(checkDisconnectAndMutate, 0);
-    }
-
-    function checkDisconnectAndMutate() {
-      // ...can childList changes be observed at all.
-
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations[0].addedNodes.length, 1);
-      assert.equal(mutations[0].addedNodes[0], removedDiv1);
-
-      mutations = null;
-      observer.disconnect();
-      removedDiv1 = div.appendChild(document.createElement('div'));
-      setTimeout(checkNotDeliveredAndMutateMultiple, 0);
-    }
-
-    function checkNotDeliveredAndMutateMultiple() {
-      // ...observer.disconnect() should prevent further delivery of mutations.
-
-      assert.equal(mutations, null);
-      observer.observe(div, { childList: true });
-      removedDiv1 = div.removeChild(div.firstChild);
-      removedDiv2 = div.removeChild(div.firstChild);
-      setTimeout(finish);
-    }
-
-    function finish() {
-      // ...re-observing after disconnect works with the same observer.
-
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations[0].removedNodes.length, 1);
-      assert.equal(mutations[0].removedNodes[0], removedDiv1);
-      assert.equal(mutations[1].type, "childList");
-      assert.equal(mutations[1].removedNodes.length, 1);
-      assert.equal(mutations[1].removedNodes[0], removedDiv2);
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle observing without specifying "childList" does not result in hearing about childList changes', function(done) {
-    var div;
-    var observer;
-    var mutations;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-      });
-
-      observer.observe(div, { attributes: true, characterData: true });
-      div.appendChild(document.createElement('div'));
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations, null);
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle re-observing the same node with the same observer has the effect of resetting the options', function(done) {
-    var div;
-    var observer;
-    var mutations;
-    var calls = 0;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-        calls++;
-      });
-
-      observer.observe(div, { childList: true, characterData: true });
-      observer.observe(div, { childList: true });
-      div.appendChild(document.createElement('div'));
-      setTimeout(checkDisconnectAndMutate, 0);
-    }
-
-    function checkDisconnectAndMutate() {
-      assert.equal(calls, 1);
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      mutations = null;
-      observer.observe(div, { childList: true, characterData: true });
-      observer.observe(div, { attributes: true });
-      div.appendChild(document.createElement('div'));
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations, null);
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle multiple observers can be registered to a given node and both receive mutations', function(done) {
-    var div;
-    var observer;
-    var observer2;
-    var mutations;
-    var mutations2;
-
-    function start() {
-      div = document.createElement('div');
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-      });
-      observer2 = new MutationObserver(function(m) {
-        mutations2 = m;
-      });
-      observer.observe(div, { childList: true });
-      observer2.observe(div, { childList: true });
-      div.appendChild(document.createElement('div'));
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations2.length, 1);
-      assert.equal(mutations2[0].type, "childList");
-      observer.disconnect();
-      observer2.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should create minimal mutations for replaceChild', function(done) {
-    var div;
-    var observer;
-    var fragment;
-    var mutations;
-    var addedDiv1;
-    var addedDiv2;
-    var removedDiv1;
-
-    function start() {
-      div = document.createElement('div');
-
-      var first = document.createElement('span');
-      first.textContent = 'Foo';
-      div.appendChild(first);
-
-      var second = document.createElement('div');
-      second.textContent = 'Bar';
-      div.appendChild(second);
-
-      removedDiv1 = div.firstChild;
-
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-      });
-
-      observer.observe(div, { childList: true });
-      addedDiv1 = document.createElement('div');
-      div.replaceChild(addedDiv1, div.firstChild);
-      setTimeout(checkReplaceWithNode, 0);
-    }
-
-    function checkReplaceWithNode() {
-      // ...simple replace child
-
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations[0].addedNodes.length, 1);
-      assert.equal(mutations[0].addedNodes[0], addedDiv1);
-      assert.equal(mutations[0].removedNodes.length, 1);
-      assert.equal(mutations[0].removedNodes[0], removedDiv1);
-
-      mutations = null;
-      fragment = document.createDocumentFragment();
-      addedDiv1 = fragment.appendChild(document.createElement('div'));
-      addedDiv2 = fragment.appendChild(document.createElement('div'));
-      removedDiv1 = div.firstChild;
-
-      div.replaceChild(fragment, removedDiv1);
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...replace with DocumentFragment.
-
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations[0].addedNodes.length, 2);
-      assert.equal(mutations[0].addedNodes[0], addedDiv1);
-      assert.equal(mutations[0].addedNodes[1], addedDiv2);
-      assert.equal(mutations[0].removedNodes.length, 1);
-      assert.equal(mutations[0].removedNodes[0], removedDiv1);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should create minimal mutations for insertBefore', function(done) {
-    var div;
-    var observer;
-    var fragment;
-    var mutations;
-    var addedDiv1;
-    var addedDiv2;
-
-    function start() {
-      div = document.createElement('div');
-
-      var first = document.createElement('span');
-      first.textContent = 'Foo';
-      div.appendChild(first);
-
-      fragment = document.createDocumentFragment();
-      addedDiv1 = fragment.appendChild(document.createElement('div'));
-      addedDiv2 = fragment.appendChild(document.createElement('div'));
-
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-      });
-
-      observer.observe(div, { childList: true });
-      div.insertBefore(fragment, div.firstChild);
-      setTimeout(finish, 0);
-    }
-
-
-    function finish() {
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations[0].addedNodes.length, 2);
-      assert.equal(mutations[0].addedNodes[0], addedDiv1);
-      assert.equal(mutations[0].addedNodes[1], addedDiv2);
-      assert.equal(mutations[0].removedNodes.length, 0);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should create minimal mutations for appendChild', function(done) {
-    var div;
-    var observer;
-    var fragment;
-    var mutations;
-    var addedDiv1;
-    var addedDiv2;
-
-    function start() {
-      div = document.createElement('div');
-
-      var first = document.createElement('span');
-      first.textContent = 'Foo';
-      div.appendChild(first);
-
-      fragment = document.createDocumentFragment();
-      addedDiv1 = fragment.appendChild(document.createElement('div'));
-      addedDiv2 = fragment.appendChild(document.createElement('div'));
-
-      observer = new MutationObserver(function(m) {
-        mutations = m;
-      });
-
-      observer.observe(div, { childList: true });
-      div.appendChild(fragment);
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "childList");
-      assert.equal(mutations[0].addedNodes.length, 2);
-      assert.equal(mutations[0].addedNodes[0], addedDiv1);
-      assert.equal(mutations[0].addedNodes[1], addedDiv2);
-      assert.equal(mutations[0].removedNodes.length, 0);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-});
-</script>
-</body>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-exceptions-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-exceptions-expected.txt
deleted file mode 100644
index e7ecccc69b..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-exceptions-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver observe should throw on invalid input
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-exceptions.sky b/engine/src/flutter/tests/mutation-observer/observe-exceptions.sky
deleted file mode 100644
index 973940396f..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-exceptions.sky
+++ /dev/null
@@ -1,54 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver observe', function() {
-  it('should throw on invalid input', function() {
-    var div = document.createElement('div');
-    var observer = new MutationObserver(function(mutations) { });
-    assert.throw(function() {
-      observer.observe();
-    });
-    assert.throw(function() {
-      observer.observe(null);
-    });
-    assert.throw(function() {
-      observer.observe(undefined)
-    });
-    assert.throw(function() {
-      observer.observe(div);
-    });
-    assert.throw(function() {
-      observer.observe(div, null);
-    });
-    assert.throw(function() {
-      observer.observe(div, undefined);
-    });
-    assert.throw(function() {
-      observer.observe(null, {attributes: true});
-    });
-    assert.throw(function() {
-      observer.observe(undefined, {attributes: true});
-    });
-    assert.throw(function() {
-      observer.observe(div, {subtree: true});
-    });
-    assert.throw(function() {
-      observer.observe(div, {attributes: false, attributeOldValue: true});
-    });
-    assert.throw(function() {
-      observer.observe(div, {attributes: false, attributeFilter: ["id"]});
-    });
-    assert.throw(function() {
-      observer.observe(div, {attributes: false, attributeOldValue: false});
-    });
-    assert.throw(function() {
-      observer.observe(div, {characterData: false, characterDataOldValue: true});
-    });
-    assert.throw(function() {
-      observer.observe(div, {characterData: false, characterDataOldValue: false});
-    });
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-options-attributes-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-options-attributes-expected.txt
deleted file mode 100644
index 1f3904a61e..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-options-attributes-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver.observe should observe attributes
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-options-attributes.sky b/engine/src/flutter/tests/mutation-observer/observe-options-attributes.sky
deleted file mode 100644
index db1f22bfda..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-options-attributes.sky
+++ /dev/null
@@ -1,34 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver.observe', function() {
-  it('should observe attributes', function() {
-    var observer = new MutationObserver(function() {});
-    var element = document.createElement('div');
-    element.setAttribute('data-test', '1');
-
-    observer.observe(element, {attributeOldValue: true});
-    element.setAttribute('data-test', '2');
-    var records = observer.takeRecords();
-    assert.equal(records.length, 1);
-    assert.equal(records[0].oldValue, 1);
-    observer.disconnect();
-
-    observer.observe(element, {attributeOldValue: false});
-    element.setAttribute('data-test', '3');
-    var records = observer.takeRecords();
-    assert.equal(records.length, 1);
-    assert.isNull(records[0].oldValue);
-    observer.disconnect();
-
-    observer.observe(element, {attributeFilter: ['data-test']});
-    element.setAttribute('data-test', '4');
-    var records = observer.takeRecords();
-    assert.equal(records.length, 1);
-    assert.isNull(records[0].oldValue);
-    observer.disconnect();
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-options-character-data-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-options-character-data-expected.txt
deleted file mode 100644
index aedc61cc53..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-options-character-data-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 Test MutationObserver.observe should respect character data options
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-options-character-data.sky b/engine/src/flutter/tests/mutation-observer/observe-options-character-data.sky
deleted file mode 100644
index 698abe0732..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-options-character-data.sky
+++ /dev/null
@@ -1,26 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('Test MutationObserver.observe', function() {
-  it('should respect character data options', function() {
-    var observer = new MutationObserver(function() {});
-    var text = new Text('0');
-
-    observer.observe(text, {characterDataOldValue: true});
-    text.data = '1';
-    var records = observer.takeRecords();
-    assert.equal(records.length, 1);
-    assert.equal(records[0].oldValue, 0);
-    observer.disconnect();
-
-    observer.observe(text, {characterDataOldValue: false});
-    text.data = '2';
-    var records = observer.takeRecords();
-    assert.equal(records.length, 1);
-    assert.isNull(records[0].oldValue);
-    observer.disconnect();
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observe-subtree-expected.txt b/engine/src/flutter/tests/mutation-observer/observe-subtree-expected.txt
deleted file mode 100644
index 9ae9a7faa6..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-subtree-expected.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-Running 5 tests
-ok 1 MutationObserver.observe on a subtree should handle basic aspects of subtree observation
-ok 2 MutationObserver.observe on a subtree should handle two observers at different depths
-ok 3 MutationObserver.observe on a subtree should handle one observer at two different depths
-ok 4 MutationObserver.observe on a subtree should handle transiently detached nodes are still observed via subtree
-ok 5 MutationObserver.observe on a subtree should have correct behavior of transient observation with complex movement
-5 tests
-5 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/observe-subtree.sky b/engine/src/flutter/tests/mutation-observer/observe-subtree.sky
deleted file mode 100644
index 98800a1d88..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observe-subtree.sky
+++ /dev/null
@@ -1,267 +0,0 @@
-<!DOCTYPE html>
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver.observe on a subtree', function() {
-  it('should handle basic aspects of subtree observation', function(done) {
-    var observer;
-    var subDiv;
-    var mutations;
-
-    function start() {
-      var div = document.createElement('div');
-      subDiv = div.appendChild(document.createElement('div'));
-      subDiv.textContent = 'hello, world';
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      observer.observe(div, {attributes: true, characterData: true, subtree: true});
-      subDiv.setAttribute('foo', 'bar');
-      subDiv.firstChild.textContent = 'goodbye!';
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...attribute and characterData changes in subtree
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[1].type, "characterData");
-      assert.equal(mutations[1].target, subDiv.firstChild);
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle two observers at different depths', function(done) {
-    var observer;
-    var observer2;
-    var mutations;
-    var mutations2;
-    var subDiv;
-
-    function start() {
-      var div = document.createElement('div');
-      subDiv = div.appendChild(document.createElement('div'));
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-      observer2 = new MutationObserver(function(records) {
-        mutations2 = records;
-      });
-
-      observer.observe(div, {attributes: true, subtree: true});
-      observer2.observe(subDiv, {attributes: true});
-      subDiv.setAttribute('foo', 'bar');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations2.length, 1);
-      assert.equal(mutations2[0].type, "attributes");
-      assert.equal(mutations2[0].target, subDiv);
-      assert.equal(mutations2[0].attributeName, "foo");
-      observer.disconnect();
-      observer2.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should handle one observer at two different depths', function(done) {
-    var observer;
-    var mutations;
-    var calls = 0;
-    var subDiv;
-
-    function start() {
-      var div = document.createElement('div');
-      subDiv = div.appendChild(document.createElement('div'));
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-        ++calls;
-      });
-
-      observer.observe(div, {attributes: true, subtree: true});
-      observer.observe(subDiv, {attributes: true, subtree: true});
-      subDiv.setAttribute('foo', 'bar');
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      assert.equal(calls, 1);
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "foo");
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  // FIXME(sky): This test is huge, it should be broken up.
-  it('should handle transiently detached nodes are still observed via subtree', function(done) {
-    var observer;
-    var mutations;
-    var div;
-    var subDiv;
-
-    function start() {
-      div = document.createElement('div');
-      subDiv = div.appendChild(document.createElement('div'));
-      subDiv.textContent = 'hello, world';
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      observer.observe(div, {attributes: true, characterData: true, subtree: true});
-      subDiv.setAttribute('foo', 'bar');
-      div.removeChild(subDiv);
-      subDiv.setAttribute('test', 'test');
-      setTimeout(checkDeliveredAndChangeAgain, 0);
-    }
-
-    function checkDeliveredAndChangeAgain() {
-      // ...both changes should be received. Change detached subDiv again.
-
-      assert.equal(mutations.length, 2);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "foo");
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].target, subDiv);
-      assert.equal(mutations[1].attributeName, "test");
-
-      mutations = null;
-      subDiv.setAttribute('foo', 'baz');
-
-      setTimeout(checkNotDeliveredAndReattach, 0);
-    }
-
-    function checkNotDeliveredAndReattach() {
-      // ...transient subtree observation was stopped after delivery, so subDiv change should not be received. Reattach and change again.
-
-      assert.equal(mutations, null);
-
-      mutations = null
-      div.appendChild(subDiv);
-      subDiv.setAttribute('foo', 'bat');
-
-      setTimeout(checkDeliveredAndReobserve, 0);
-    }
-
-    function checkDeliveredAndReobserve() {
-      //...reattached subtree should now be observable. Try detaching and re-observing.
-
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "foo");
-
-      mutations = null;
-      div.removeChild(subDiv);
-      subDiv.firstChild.textContent = 'badbye';
-      observer.observe(div, {attributes: true, characterData: true, subtree: true});
-      subDiv.setAttribute('foo', 'boo');
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...The change made before re-observing should be received, but not the one after.
-
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "characterData");
-      assert.equal(mutations[0].target, subDiv.firstChild);
-
-      observer.disconnect();
-      done();
-    }
-
-    start();
-  });
-
-  it('should have correct behavior of transient observation with complex movement', function(done) {
-    var observer;
-    var text;
-    var subDiv;
-    var mutations;
-    var subDiv2;
-    var subDiv3;
-
-    function start() {
-      var div = document.createElement('div');
-      subDiv = div.appendChild(document.createElement('div'));
-      subDiv2 = subDiv.appendChild(document.createElement('div'));
-      subDiv2.textContent = 'hello, world';
-      subDiv3 = document.createElement('div');
-
-      observer = new MutationObserver(function(records) {
-        mutations = records;
-      });
-
-      observer.observe(div, {attributes: true, characterData: true, subtree: true});
-      div.removeChild(subDiv);
-      subDiv.removeChild(subDiv2);
-      text = subDiv2.removeChild(subDiv2.firstChild);
-
-      subDiv.setAttribute('a', 'a');
-      subDiv2.setAttribute('b', 'b');
-      text.textContent = 'c';
-      subDiv3.appendChild(subDiv2);
-      subDiv3.setAttribute('d', 'd');
-      subDiv2.setAttribute('e', 'e');
-      div.appendChild(subDiv3);
-      subDiv3.setAttribute('f', 'f');
-      subDiv2.setAttribute('g', 'g');
-
-      setTimeout(finish, 0);
-    }
-
-    function finish() {
-      // ...All changes should be received except for setting the "d" attribute on subDiv3 before it was reachable from div.
-
-      assert.equal(mutations.length, 6);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "a");
-
-      assert.equal(mutations[1].type, "attributes");
-      assert.equal(mutations[1].target, subDiv2);
-      assert.equal(mutations[1].attributeName, "b");
-
-      assert.equal(mutations[2].type, "characterData");
-      assert.equal(mutations[2].target, text);
-
-      assert.equal(mutations[3].type, "attributes");
-      assert.equal(mutations[3].target, subDiv2);
-      assert.equal(mutations[3].attributeName, "e");
-
-      assert.equal(mutations[4].type, "attributes");
-      assert.equal(mutations[4].target, subDiv3);
-      assert.equal(mutations[4].attributeName, "f");
-
-      assert.equal(mutations[5].type, "attributes");
-      assert.equal(mutations[5].target, subDiv2);
-      assert.equal(mutations[5].attributeName, "g");
-
-      observer.disconnect();
-      done();
-    }
-    start();
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observer-wrapper-dropoff-transient.sky b/engine/src/flutter/tests/mutation-observer/observer-wrapper-dropoff-transient.sky
deleted file mode 100644
index 30465437c5..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observer-wrapper-dropoff-transient.sky
+++ /dev/null
@@ -1,29 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver wrappers', function() {
-    it('should survive GC for passing into the callback even if JS has lost references and the only remaining observations are transient.', function(done) {
-        function addObserver(node, fn) {
-            var observer = new MutationObserver(fn);
-            observer.testProperty = true;
-            observer.observe(node, {attributes:true, subtree: true});
-        }
-
-        var root = document.createElement('div');
-        var child = root.appendChild(document.createElement('span'));
-        addObserver(root, function(records, observer) {
-            window.observer = observer;
-            assert.ok(observer.testProperty);
-            done();
-        });
-
-        root.removeChild(child);
-        child.setAttribute('foo', 'bar');
-        root = null;
-
-        gc();
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/observer-wrapper-dropoff.sky b/engine/src/flutter/tests/mutation-observer/observer-wrapper-dropoff.sky
deleted file mode 100644
index b7f76ba1fa..0000000000
--- a/engine/src/flutter/tests/mutation-observer/observer-wrapper-dropoff.sky
+++ /dev/null
@@ -1,28 +0,0 @@
-<!DOCTYPE html>
-
-<script src="../../../resources/js-test.js"></script>
-
-<script>
-description('MutationObserver wrappers should survive GC for passing into the callback even if JS has lost references.');
-
-jsTestIsAsync = true;
-
-function addObserver(node, fn) {
-    var observer = new MutationObserver(fn);
-    observer.testProperty = true;
-    observer.observe(node, {attributes:true});
-}
-
-window.addEventListener("load", function() {
-    addObserver(document.body, function(records, observer) {
-        window.observer = observer;
-        shouldBe('observer.testProperty', 'true');
-        finishJSTest();
-    });
-
-    gc();
-
-    document.body.setAttribute('touch', 'the node');
-});
-</script>
-
diff --git a/engine/src/flutter/tests/mutation-observer/script-append-expected.txt b/engine/src/flutter/tests/mutation-observer/script-append-expected.txt
deleted file mode 100644
index 3e59fd9040..0000000000
--- a/engine/src/flutter/tests/mutation-observer/script-append-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver should not invoke callbacks when appending a script
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/script-append.sky b/engine/src/flutter/tests/mutation-observer/script-append.sky
deleted file mode 100644
index fa2d747727..0000000000
--- a/engine/src/flutter/tests/mutation-observer/script-append.sky
+++ /dev/null
@@ -1,27 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver', function() {
-    it('should not invoke callbacks when appending a script', function() {
-        var mutationsDelivered = false;
-        function callback(mutations) {
-            mutationsDelivered = true;
-        }
-
-        var observer = new MutationObserver(callback);
-        var div = document.createElement('div');
-        observer.observe(div, {attributes: true});
-        div.setAttribute('foo', 'bar');
-        assert.notOk(mutationsDelivered);
-        var scriptDidRun = false;
-        var script = document.createElement('script');
-        script.textContent = 'scriptDidRun = true';
-        assert.notOk(scriptDidRun);
-        document.documentElement.appendChild(script);
-        assert.notOk(scriptDidRun);
-        assert.notOk(mutationsDelivered);
-    });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/shadow-dom-expected.txt b/engine/src/flutter/tests/mutation-observer/shadow-dom-expected.txt
deleted file mode 100644
index 2c9b2cde2b..0000000000
--- a/engine/src/flutter/tests/mutation-observer/shadow-dom-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObservers should handle shadow dom
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/shadow-dom.sky b/engine/src/flutter/tests/mutation-observer/shadow-dom.sky
deleted file mode 100644
index 9be869decd..0000000000
--- a/engine/src/flutter/tests/mutation-observer/shadow-dom.sky
+++ /dev/null
@@ -1,40 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<div id="range"></div>
-<script>
-describe('MutationObservers', function() {
-  it('should handle shadow dom', function() {
-    function mutate(element) {
-      element.setAttribute('data-foo', 'bar');
-      element.insertBefore(new Text('hello'), element.firstChild);
-      element.firstChild.textContent = 'goodbye';
-      element.removeChild(element.firstChild);
-    }
-
-    var range = document.getElementById('range');
-    var shadowRoot = range.ensureShadowRoot();
-    shadowRoot.appendChild(document.createElement('div'));
-    var observer = new MutationObserver(function() { });
-
-    observer.observe(shadowRoot.firstChild, {attributes: true, childList: true, characterData: true, subtree: true});
-    mutate(shadowRoot.firstChild);
-
-    var mutations = observer.takeRecords();
-    // Mutations in shadow DOM should have been observed:
-    assert.equal(mutations.length, 4);
-    assert.equal(mutations[0].type, "attributes");
-    assert.equal(mutations[1].type, "childList");
-    assert.equal(mutations[2].type, "characterData");
-    assert.equal(mutations[3].type, "childList");
-    observer.disconnect();
-
-    mutations = observer.takeRecords();
-    observer.observe(document, {attributes: true, childList: true, characterData: true, subtree: true});
-    mutate(shadowRoot.firstChild);
-    // Observing from outside shadow DOM should not see mutations in the shadow:
-    assert.equal(mutations.length, 0);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/takeRecords-expected.txt b/engine/src/flutter/tests/mutation-observer/takeRecords-expected.txt
deleted file mode 100644
index 3dcb0acd9b..0000000000
--- a/engine/src/flutter/tests/mutation-observer/takeRecords-expected.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-Running 1 tests
-ok 1 MutationObserver.takeRecords should allow taking records synchronously or getting a notification
-1 tests
-1 pass
-0 fail
diff --git a/engine/src/flutter/tests/mutation-observer/takeRecords.sky b/engine/src/flutter/tests/mutation-observer/takeRecords.sky
deleted file mode 100644
index ba8a274aec..0000000000
--- a/engine/src/flutter/tests/mutation-observer/takeRecords.sky
+++ /dev/null
@@ -1,53 +0,0 @@
-<html>
-<import src="../resources/chai.sky" />
-<import src="../resources/mocha.sky" />
-<script>
-describe('MutationObserver.takeRecords', function() {
-  it('should allow taking records synchronously or getting a notification', function(done) {
-    var mutations;
-    var div;
-    var subDiv;
-    var observer;
-
-    // Testing takeRecords.
-    mutations = null;
-    div = document.createElement('div');
-    subDiv = div.appendChild(document.createElement('div'));
-    subDiv.textContent = 'hello, world';
-    observer = new MutationObserver(function(records) {
-      mutations = records;
-    });
-
-    observer.observe(div, {attributes: true, characterData: true, subtree: true});
-    subDiv.setAttribute('foo', 'bar');
-    subDiv.firstChild.textContent = 'goodbye!';
-    div.removeChild(subDiv);
-
-    mutations = observer.takeRecords();
-
-    // ...records are taken synchronously.
-
-    assert.equal(mutations.length, 2);
-    assert.equal(mutations[0].type, "attributes");
-    assert.equal(mutations[0].target, subDiv);
-    assert.equal(mutations[0].attributeName, "foo");
-    assert.equal(mutations[1].type, "characterData");
-    assert.equal(mutations[1].target, subDiv.firstChild);
-
-    subDiv.setAttribute('foo', 'baz');
-
-    setTimeout(function() {
-      // ...takeRecord took records, but did not clear transient observers.
-
-      assert.equal(mutations.length, 1);
-      assert.equal(mutations[0].type, "attributes");
-      assert.equal(mutations[0].target, subDiv);
-      assert.equal(mutations[0].attributeName, "foo");
-      observer.disconnect();
-
-      done();
-    }, 0);
-  });
-});
-</script>
-</html>
diff --git a/engine/src/flutter/tests/mutation-observer/transient-gc-crash.sky b/engine/src/flutter/tests/mutation-observer/transient-gc-crash.sky
deleted file mode 100644
index e6d4bb6af4..0000000000
--- a/engine/src/flutter/tests/mutation-observer/transient-gc-crash.sky
+++ /dev/null
@@ -1,22 +0,0 @@
-<script src="../../../resources/js-test.js"></script>
-<script>
-window.jsTestIsAsync = true;
-description('Clearing transient observers after observation node is GCed should not cause a crash.');
-
-function callback(mutations) {
-    window.mutations = mutations;
-}
-var observer = new MutationObserver(callback);
-
-var div = document.createElement('div');
-var span = div.appendChild(document.createElement('span'));
-observer.observe(div, {attributes: true, subtree: true});
-div.removeChild(span);
-div = null;
-gc();
-span.setAttribute('foo', 'bar');
-setTimeout(function() {
-    shouldBe('mutations.length', '1');
-    finishJSTest();
-}, 0);
-</script>
diff --git a/engine/src/flutter/tests/mutation-observer/weak-callback-gc-crash.sky b/engine/src/flutter/tests/mutation-observer/weak-callback-gc-crash.sky
deleted file mode 100644
index 4cb6819f14..0000000000
--- a/engine/src/flutter/tests/mutation-observer/weak-callback-gc-crash.sky
+++ /dev/null
@@ -1,17 +0,0 @@
-<!DOCTYPE html>
-<div>Test passes if it does not crash</div>
-<script src="../../../resources/gc.js"></script>
-<script>
-if (window.testRunner) {
-    testRunner.waitUntilDone();
-    testRunner.dumpAsText();
-}
-var observer = new MutationObserver(function() {console.log('Should not appear')});
-var div = document.createElement('div');
-observer.observe(div, {attributes: true});
-div.id = 'foo';
-div = null;
-observer = null;
-gc();
-setTimeout(function() { testRunner.notifyDone(); }, 0);
-</script>