[web][debug] Remove RequireJS timeouts for debug builds. (#107868)

packages/flutter_tools/lib/src/web/bootstrap.dart

@@ -28,6 +28,7 @@ var styles = `
     position: absolute;
     top: 0px;
     left: 0px;
+    overflow: hidden;
   }
 
   .indeterminate {
@@ -131,6 +132,10 @@ String generateMainModule({
 }) {
   return '''
 /* ENTRYPOINT_EXTENTION_MARKER */
+// Disable require module timeout
+require.config({
+  waitSeconds: 0
+});
 // Create the main module loaded below.
 define("$bootstrapModule", ["$entrypoint", "dart_sdk"], function(app, dart_sdk) {
   dart_sdk.dart.setStartAsyncSynchronously(true);

packages/flutter_tools/test/general.shard/web/bootstrap_test.dart

@@ -21,7 +21,7 @@ void main() {
     expect(result, contains('requireEl.setAttribute("data-main", "main_module.bootstrap");'));
   });
 
-test('generateBootstrapScript includes loading indicator', () {
+  test('generateBootstrapScript includes loading indicator', () {
     final String result = generateBootstrapScript(
       requireUrl: 'require.js',
       mapperUrl: 'mapper.js',
@@ -30,6 +30,36 @@ test('generateBootstrapScript includes loading indicator', () {
     expect(result, contains('"indeterminate"'));
   });
 
+  // https://github.com/flutter/flutter/issues/107742
+  test('generateBootstrapScript loading indicator does not trigger scrollbars', () {
+    final String result = generateBootstrapScript(
+      requireUrl: 'require.js',
+      mapperUrl: 'mapper.js',
+    );
+
+    // See: https://regexr.com/6q0ft
+    final RegExp regex = RegExp(r'(?:\.flutter-loader\s*\{)[^}]+(?:overflow\:\s*hidden;)[^}]+}');
+
+    expect(result, matches(regex), reason: '.flutter-loader must have overflow: hidden');
+  });
+
+  // https://github.com/flutter/flutter/issues/82524
+  test('generateMainModule removes timeout from requireJS', () {
+    final String result = generateMainModule(
+      entrypoint: 'foo/bar/main.js',
+      nullAssertions: false,
+      nativeNullAssertions: false,
+    );
+
+    // See: https://regexr.com/6q0kp
+    final RegExp regex = RegExp(
+      r'(?:require\.config\(\{)(?:.|\s(?!\}\);))*'
+        r'(?:waitSeconds\:\s*0[,]?)'
+      r'(?:(?!\}\);).|\s)*\}\);');
+
+    expect(result, matches(regex), reason: 'require.config must have a waitSeconds: 0 config entry');
+  });
+
   test('generateMainModule embeds urls correctly', () {
     final String result = generateMainModule(
       entrypoint: 'foo/bar/main.js',