[ios][pv]fully revert the UIScreen.main deprecated API change (#166080)

This PR fully reverts https://github.com/flutter/flutter/pull/162785

Due to crash from an internal customer

Fixes https://github.com/flutter/flutter/issues/165648


## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [ ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

---------

Co-authored-by: Jenn Magder <magder@google.com>

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm

@@ -249,6 +249,10 @@ static BOOL _preparedOnce = NO;
   CGRect rectSoFar_;
 }
 
+- (instancetype)initWithFrame:(CGRect)frame {
+  return [self initWithFrame:frame screenScale:[UIScreen mainScreen].scale];
+}
+
 - (instancetype)initWithFrame:(CGRect)frame screenScale:(CGFloat)screenScale {
   if (self = [super initWithFrame:frame]) {
     self.backgroundColor = UIColor.clearColor;
@@ -463,11 +467,12 @@ static BOOL _preparedOnce = NO;
   return self;
 }
 
-- (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame screenScale:(CGFloat)screenScale {
+- (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame {
   FML_DCHECK(self.pool.count <= self.capacity);
   if (self.pool.count == 0) {
     // The pool is empty, alloc a new one.
-    return [[FlutterClippingMaskView alloc] initWithFrame:frame screenScale:screenScale];
+    return [[FlutterClippingMaskView alloc] initWithFrame:frame
+                                              screenScale:UIScreen.mainScreen.scale];
   }
   FlutterClippingMaskView* maskView = [self.pool anyObject];
   maskView.frame = frame;

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViewsController.mm

@@ -12,7 +12,6 @@
 #include "flutter/fml/synchronization/count_down_latch.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterOverlayView.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterView.h"
-#import "flutter/shell/platform/darwin/ios/framework/Source/UIViewController+FlutterScreenAndSceneIfLoaded.h"
 #include "flutter/shell/platform/darwin/ios/framework/Source/overlay_layer_pool.h"
 #import "flutter/shell/platform/darwin/ios/ios_surface.h"
 
@@ -209,8 +208,7 @@ static CGRect GetCGRectFromDlRect(const DlRect& clipDlRect) {
 
 /// Runs on the platform thread.
 - (void)createLayerWithIosContext:(const std::shared_ptr<flutter::IOSContext>&)iosContext
-                      pixelFormat:(MTLPixelFormat)pixelFormat
-                      screenScale:(CGFloat)screenScale;
+                      pixelFormat:(MTLPixelFormat)pixelFormat;
 
 /// Removes overlay views and platform views that aren't needed in the current frame.
 /// Must run on the platform thread.
@@ -484,9 +482,7 @@ static CGRect GetCGRectFromDlRect(const DlRect& clipDlRect) {
   CGRect frame =
       CGRectMake(-clipView.frame.origin.x, -clipView.frame.origin.y,
                  CGRectGetWidth(self.flutterView.bounds), CGRectGetHeight(self.flutterView.bounds));
-  clipView.maskView = [self.maskViewPool
-      getMaskViewWithFrame:frame
-               screenScale:[self.flutterViewController flutterScreenIfViewLoaded].scale];
+  clipView.maskView = [self.maskViewPool getMaskViewWithFrame:frame];
 }
 
 - (void)applyMutators:(const flutter::MutatorsStack&)mutatorsStack
@@ -508,7 +504,7 @@ static CGRect GetCGRectFromDlRect(const DlRect& clipDlRect) {
     [self.maskViewPool insertViewToPoolIfNeeded:(FlutterClippingMaskView*)(clipView.maskView)];
     clipView.maskView = nil;
   }
-  CGFloat screenScale = [self.flutterViewController flutterScreenIfViewLoaded].scale;
+  CGFloat screenScale = [UIScreen mainScreen].scale;
   auto iter = mutatorsStack.Begin();
   while (iter != mutatorsStack.End()) {
     switch ((*iter)->GetType()) {
@@ -636,7 +632,7 @@ static CGRect GetCGRectFromDlRect(const DlRect& clipDlRect) {
   // when we apply the transforms matrix in |applyMutators:embeddedView:boundingRect|, we need
   // to remember to do a reverse translate.
   const SkRect& rect = params.finalBoundingRect();
-  CGFloat screenScale = [self.flutterViewController flutterScreenIfViewLoaded].scale;
+  CGFloat screenScale = [UIScreen mainScreen].scale;
   clippingView.frame = CGRectMake(rect.x() / screenScale, rect.y() / screenScale,
                                   rect.width() / screenScale, rect.height() / screenScale);
   [self applyMutators:mutatorStack embeddedView:touchInterceptor boundingRect:rect];
@@ -796,8 +792,7 @@ static CGRect GetCGRectFromDlRect(const DlRect& clipDlRect) {
       self.platformTaskRunner, [self, missingLayerCount, iosContext, latch]() {
         for (auto i = 0u; i < missingLayerCount; i++) {
           [self createLayerWithIosContext:iosContext
-                              pixelFormat:((FlutterView*)self.flutterView).pixelFormat
-                              screenScale:((FlutterView*)self.flutterView).screen.scale];
+                              pixelFormat:((FlutterView*)self.flutterView).pixelFormat];
         }
         latch->CountDown();
       });
@@ -901,9 +896,8 @@ static CGRect GetCGRectFromDlRect(const DlRect& clipDlRect) {
 }
 
 - (void)createLayerWithIosContext:(const std::shared_ptr<flutter::IOSContext>&)iosContext
-                      pixelFormat:(MTLPixelFormat)pixelFormat
-                      screenScale:(CGFloat)screenScale {
-  self.layerPool->CreateLayer(iosContext, pixelFormat, screenScale);
+                      pixelFormat:(MTLPixelFormat)pixelFormat {
+  self.layerPool->CreateLayer(iosContext, pixelFormat);
 }
 
 - (void)removeUnusedLayers:(const std::vector<std::shared_ptr<flutter::OverlayLayer>>&)unusedLayers

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViewsTest.mm

@@ -16,7 +16,6 @@
 #include "flutter/fml/thread.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterMacros.h"
 #import "flutter/shell/platform/darwin/ios/framework/Headers/FlutterViewController.h"
-#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterEngine_Test.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViewsController.h"
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h"
@@ -235,24 +234,6 @@ const float kFloatCompareEpsilon = 0.001;
 }
 @end
 
-@interface FlutterPlatformViewsTestMockFlutterViewController : FlutterViewController
-
-- (UIScreen*)flutterScreenIfViewLoaded;
-
-@end
-
-@implementation FlutterPlatformViewsTestMockFlutterViewController
-
-- (UIScreen*)flutterScreenIfViewLoaded {
-  UIScreen* mockScreen = OCMClassMock([UIScreen class]);
-  CGFloat screenScale = 3;
-  OCMStub([mockScreen scale]).andReturn(screenScale);
-
-  return mockScreen;
-}
-
-@end
-
 namespace flutter {
 namespace {
 class FlutterPlatformViewsTestMockPlatformViewDelegate : public PlatformView::Delegate {
@@ -348,15 +329,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
                                                        @"viewType" : @"MockFlutterPlatformView"
                                                      }]
             result:result];
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a translate matrix
@@ -507,15 +485,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a backdrop filter
@@ -592,15 +567,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a backdrop filter
@@ -677,15 +649,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push backdrop filters
@@ -763,15 +732,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a backdrop filter
@@ -895,15 +861,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push backdrop filters
@@ -1054,15 +1017,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push backdrop filters
@@ -1361,15 +1321,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a dilate backdrop filter
@@ -1695,15 +1652,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a translate matrix
@@ -1762,15 +1716,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
 
@@ -1873,15 +1824,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a rotate matrix
@@ -1954,15 +1902,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params.
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack.
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   flutter::DlMatrix translateMatrix = flutter::DlMatrix::MakeTranslation({5, 5});
@@ -2033,15 +1978,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 30, 30)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack.
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   flutter::DlMatrix translateMatrix = flutter::DlMatrix::MakeTranslation({5, 5});
@@ -2111,15 +2053,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a clip rect
@@ -2194,15 +2133,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a clip rect
@@ -2297,15 +2233,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a clip rrect
@@ -2408,15 +2341,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a clip rrect
@@ -2536,15 +2466,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a clip path
@@ -2647,15 +2574,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a clip path
@@ -3501,10 +3425,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
   XCTAssertNotNil(gMockPlatformView);
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
-
   // Create embedded view params
   flutter::MutatorsStack stack;
   flutter::DlMatrix finalMatrix;
@@ -3622,9 +3542,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
       /*worker_task_runner=*/nil,
       /*is_gpu_disabled_jsync_switch=*/std::make_shared<fml::SyncSwitch>());
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
 
@@ -3694,9 +3611,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
       /*worker_task_runner=*/nil,
       /*is_gpu_disabled_jsync_switch=*/std::make_shared<fml::SyncSwitch>());
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
 
@@ -3804,9 +3718,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
       /*worker_task_runner=*/nil,
       /*is_gpu_disabled_jsync_switch=*/std::make_shared<fml::SyncSwitch>());
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
 
@@ -3945,13 +3856,13 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
 - (void)testFlutterClippingMaskViewPoolReuseViewsAfterRecycle {
   FlutterClippingMaskViewPool* pool = [[FlutterClippingMaskViewPool alloc] initWithCapacity:2];
-  FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero screenScale:1];
-  FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero screenScale:1];
+  FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero];
+  FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero];
   [pool insertViewToPoolIfNeeded:view1];
   [pool insertViewToPoolIfNeeded:view2];
   CGRect newRect = CGRectMake(0, 0, 10, 10);
-  FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:newRect screenScale:1];
-  FlutterClippingMaskView* view4 = [pool getMaskViewWithFrame:newRect screenScale:1];
+  FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:newRect];
+  FlutterClippingMaskView* view4 = [pool getMaskViewWithFrame:newRect];
   // view3 and view4 should randomly get either of view1 and view2.
   NSSet* set1 = [NSSet setWithObjects:view1, view2, nil];
   NSSet* set2 = [NSSet setWithObjects:view3, view4, nil];
@@ -3962,9 +3873,9 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
 
 - (void)testFlutterClippingMaskViewPoolAllocsNewMaskViewsAfterReachingCapacity {
   FlutterClippingMaskViewPool* pool = [[FlutterClippingMaskViewPool alloc] initWithCapacity:2];
-  FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero screenScale:1];
-  FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero screenScale:1];
-  FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:CGRectZero screenScale:1];
+  FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero];
+  FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero];
+  FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:CGRectZero];
   XCTAssertNotEqual(view1, view3);
   XCTAssertNotEqual(view2, view3);
 }
@@ -3973,7 +3884,7 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
   __weak UIView* weakView;
   @autoreleasepool {
     FlutterClippingMaskViewPool* pool = [[FlutterClippingMaskViewPool alloc] initWithCapacity:2];
-    FlutterClippingMaskView* view = [pool getMaskViewWithFrame:CGRectZero screenScale:1];
+    FlutterClippingMaskView* view = [pool getMaskViewWithFrame:CGRectZero];
     weakView = view;
     XCTAssertNotNil(weakView);
   }
@@ -4016,15 +3927,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
             result:result];
 
   XCTAssertNotNil(gMockPlatformView);
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack1;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack1.PushTransform(screenScaleMatrix);
   // Push a clip rect
@@ -4132,15 +4040,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
   UIView* view2 = gMockPlatformView;
 
   XCTAssertNotNil(gMockPlatformView);
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack1;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack1.PushTransform(screenScaleMatrix);
   // Push a clip rect
@@ -4212,15 +4117,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
             result:result];
 
   XCTAssertNotNil(gMockPlatformView);
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack1;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack1.PushTransform(screenScaleMatrix);
   // Push a clip rect
@@ -4294,9 +4196,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
       /*worker_task_runner=*/nil,
       /*is_gpu_disabled_jsync_switch=*/std::make_shared<fml::SyncSwitch>());
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
 
@@ -4430,15 +4329,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
                                                        @"viewType" : @"MockFlutterPlatformView"
                                                      }]
             result:result];
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a translate matrix
@@ -4503,15 +4399,12 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
                                                        @"viewType" : @"MockFlutterPlatformView"
                                                      }]
             result:result];
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a translate matrix
@@ -4578,16 +4471,13 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
                                                        @"viewType" : @"MockFlutterPlatformView"
                                                      }]
             result:result];
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
 
   // Create embedded view params
   flutter::MutatorsStack stack;
   // Layer tree always pushes a screen scale factor to the stack
-  flutter::DlScalar screenScale = [mockFlutterViewController flutterScreenIfViewLoaded].scale;
+  flutter::DlScalar screenScale = [UIScreen mainScreen].scale;
   flutter::DlMatrix screenScaleMatrix = flutter::DlMatrix::MakeScale({screenScale, screenScale, 1});
   stack.PushTransform(screenScaleMatrix);
   // Push a translate matrix
@@ -4625,14 +4515,14 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
   FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"foobar"];
   [engine run];
   XCTAssertTrue(engine.platformView != nullptr);
-  std::shared_ptr<flutter::IOSContext> ios_context = engine.platformView->GetIosContext();
+  auto ios_context = engine.platformView->GetIosContext();
 
-  flutter::OverlayLayerPool pool;
+  auto pool = flutter::OverlayLayerPool{};
 
   // Add layers to the pool.
-  pool.CreateLayer(ios_context, MTLPixelFormatBGRA8Unorm, 1);
+  pool.CreateLayer(ios_context, MTLPixelFormatBGRA8Unorm);
   XCTAssertEqual(pool.size(), 1u);
-  pool.CreateLayer(ios_context, MTLPixelFormatBGRA8Unorm, 1);
+  pool.CreateLayer(ios_context, MTLPixelFormatBGRA8Unorm);
   XCTAssertEqual(pool.size(), 2u);
 
   // Mark all layers as unused.
@@ -4645,34 +4535,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
   XCTAssertEqual(pool.size(), 1u);
 }
 
-- (void)testLayerUpdateViewStateWithNilFlutterViewShouldNotCrash {
-  // Create an IOSContext.
-  FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"foobar"];
-  [engine run];
-  XCTAssertTrue(engine.platformView != nullptr);
-  std::shared_ptr<flutter::IOSContext> ios_context = engine.platformView->GetIosContext();
-
-  flutter::OverlayLayerPool pool;
-
-  // Add layers to the pool.
-  pool.CreateLayer(ios_context, MTLPixelFormatBGRA8Unorm, 1);
-  XCTAssertEqual(pool.size(), 1u);
-
-  std::shared_ptr<flutter::OverlayLayer> layer = pool.GetNextLayer();
-
-  layer->UpdateViewState(nil, SkRect::MakeXYWH(1, 2, 3, 4), 0, 0);
-  // Should not update the view state (e.g. overlay_view_wrapper's frame) when FlutterView is nil.
-  XCTAssertTrue(CGRectEqualToRect(layer->overlay_view_wrapper.frame, CGRectZero));
-
-  FlutterView* flutterView = [[FlutterView alloc] initWithDelegate:engine
-                                                            opaque:YES
-                                                   enableWideGamut:NO];
-  layer->UpdateViewState(flutterView, SkRect::MakeXYWH(1, 2, 3, 4), 0, 0);
-  // Should not update the view state (e.g. overlay_view_wrapper's frame) when FlutterView's screen
-  // is nil.
-  XCTAssertTrue(CGRectEqualToRect(layer->overlay_view_wrapper.frame, CGRectZero));
-}
-
 - (void)testFlutterPlatformViewControllerSubmitFramePreservingFrameDamage {
   flutter::FlutterPlatformViewsTestMockPlatformViewDelegate mock_delegate;
 
@@ -4692,9 +4554,6 @@ fml::RefPtr<fml::TaskRunner> GetDefaultTaskRunner() {
       /*worker_task_runner=*/nil,
       /*is_gpu_disabled_jsync_switch=*/std::make_shared<fml::SyncSwitch>());
 
-  FlutterPlatformViewsTestMockFlutterViewController* mockFlutterViewController =
-      [[FlutterPlatformViewsTestMockFlutterViewController alloc] init];
-  flutterPlatformViewsController.flutterViewController = mockFlutterViewController;
   UIView* flutterView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
   flutterPlatformViewsController.flutterView = flutterView;
 

engine/src/flutter/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h

@@ -66,7 +66,7 @@
 - (instancetype)initWithCapacity:(NSInteger)capacity;
 
 // Reuse a maskView from the pool, or allocate a new one.
-- (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame screenScale:(CGFloat)screenScale;
+- (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame;
 
 // Insert the `maskView` into the pool.
 - (void)insertViewToPoolIfNeeded:(FlutterClippingMaskView*)maskView;

engine/src/flutter/shell/platform/darwin/ios/framework/Source/overlay_layer_pool.h

@@ -58,9 +58,7 @@ class OverlayLayerPool {
   /// @brief Create a new overlay layer.
   ///
   /// This method can only be called on the Platform thread.
-  void CreateLayer(const std::shared_ptr<IOSContext>& ios_context,
-                   MTLPixelFormat pixel_format,
-                   CGFloat screenScale);
+  void CreateLayer(const std::shared_ptr<IOSContext>& ios_context, MTLPixelFormat pixel_format);
 
   /// @brief Removes unused layers from the pool. Returns the unused layers.
   std::vector<std::shared_ptr<OverlayLayer>> RemoveUnusedLayers();

engine/src/flutter/shell/platform/darwin/ios/framework/Source/overlay_layer_pool.mm

@@ -5,7 +5,6 @@
 #include "flutter/shell/platform/darwin/ios/framework/Source/overlay_layer_pool.h"
 
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterOverlayView.h"
-#import "flutter/shell/platform/darwin/ios/framework/Source/FlutterView.h"
 #import "flutter/shell/platform/darwin/ios/ios_surface.h"
 
 namespace flutter {
@@ -23,15 +22,7 @@ void OverlayLayer::UpdateViewState(UIView* flutter_view,
                                    SkRect rect,
                                    int64_t view_id,
                                    int64_t overlay_id) {
-  FlutterView* flutterView = (FlutterView*)flutter_view;
-  // There can be a race where UpdateViewState() is called when flutter_view or flutter_view's
-  // screen is nil when app is backgrounded.
-  // It's unlikely for scale to be 0, but just to be safe here since it's used in a scaling
-  // calculation division below
-  if (!flutterView || !flutterView.screen || flutterView.screen.scale == 0.0f) {
-    return;
-  }
-  CGFloat screenScale = flutterView.screen.scale;
+  auto screenScale = [UIScreen mainScreen].scale;
   // Set the size of the overlay view wrapper.
   // This wrapper view masks the overlay view.
   overlay_view_wrapper.frame = CGRectMake(rect.x() / screenScale, rect.y() / screenScale,
@@ -62,13 +53,13 @@ std::shared_ptr<OverlayLayer> OverlayLayerPool::GetNextLayer() {
 }
 
 void OverlayLayerPool::CreateLayer(const std::shared_ptr<IOSContext>& ios_context,
-                                   MTLPixelFormat pixel_format,
-                                   CGFloat screenScale) {
+                                   MTLPixelFormat pixel_format) {
   FML_DCHECK([[NSThread currentThread] isMainThread]);
   std::shared_ptr<OverlayLayer> layer;
   UIView* overlay_view;
   UIView* overlay_view_wrapper;
 
+  CGFloat screenScale = [UIScreen mainScreen].scale;
   overlay_view = [[FlutterOverlayView alloc] initWithContentsScale:screenScale
                                                        pixelFormat:pixel_format];
   overlay_view_wrapper = [[FlutterOverlayView alloc] initWithContentsScale:screenScale
@@ -80,6 +71,7 @@ void OverlayLayerPool::CreateLayer(const std::shared_ptr<IOSContext>& ios_contex
 
   layer = std::make_shared<OverlayLayer>(overlay_view, overlay_view_wrapper, std::move(ios_surface),
                                          std::move(surface));
+
   // The overlay view wrapper masks the overlay view.
   // This is required to keep the backing surface size unchanged between frames.
   //