[ios_platform_view] only recycle maskView when the view is applying mutators (flutter/engine#41573)

A mistake was introduced in https://github.com/flutter/engine/pull/39498  where the maskViews are already recycles each frame. 

Sometimes a PlatformView does not need to be re-composite: (https://github.com/flutter/engine/blob/main/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm#L398-L401), so the mask view for such PlatformView should not be recycled.

This PR changed the `recycleMaskViews` API to allow individual maskviews to be recycled. `ApplyMutator` then only recycle the maskView for that particular PlatformView.

The MaskViewPool is also reworked to be simpler. 

- The pool now contains a single set of mask views, there is no index counter needed.
- When a maskView is needed, try to get it from the pool. 
  - If pool is empty, create a new view.
  - If pool has an available maskview, remove it from the pool.
- When a PlatformView starts to `applyMutator`, it removes current the maskView, insert the maskView to the pool.
- When the above PlatformView needs to a maskView, it grabs one from the pool. 

fixes: https://github.com/flutter/flutter/issues/125620

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

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

@@ -18,8 +18,6 @@
 #import "flutter/shell/platform/darwin/ios/framework/Source/FlutterViewController_Internal.h"
 #import "flutter/shell/platform/darwin/ios/ios_surface.h"
 
-static const NSUInteger kFlutterClippingMaskViewPoolCapacity = 5;
-
 @implementation UIView (FirstResponder)
 - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
   if (self.isFirstResponder) {
@@ -447,6 +445,8 @@ void FlutterPlatformViewsController::ClipViewSetMaskView(UIView* clipView) {
   clipView.maskView = [mask_view_pool_.get() getMaskViewWithFrame:frame];
 }
 
+// This method is only called when the `embedded_view` needs to be re-composited at the current
+// frame. See: `CompositeWithParams` for details.
 void FlutterPlatformViewsController::ApplyMutators(const MutatorsStack& mutators_stack,
                                                    UIView* embedded_view,
                                                    const SkRect& bounding_rect) {
@@ -461,12 +461,10 @@ void FlutterPlatformViewsController::ApplyMutators(const MutatorsStack& mutators
   NSMutableArray* blurFilters = [[[NSMutableArray alloc] init] autorelease];
   FML_DCHECK(!clipView.maskView ||
              [clipView.maskView isKindOfClass:[FlutterClippingMaskView class]]);
-  if (mask_view_pool_.get() == nil) {
-    mask_view_pool_.reset([[FlutterClippingMaskViewPool alloc]
-        initWithCapacity:kFlutterClippingMaskViewPoolCapacity]);
+  if (clipView.maskView) {
+    [mask_view_pool_.get() insertViewToPoolIfNeeded:(FlutterClippingMaskView*)(clipView.maskView)];
+    clipView.maskView = nil;
   }
-  [mask_view_pool_.get() recycleMaskViews];
-  clipView.maskView = nil;
   CGFloat screenScale = [UIScreen mainScreen].scale;
   auto iter = mutators_stack.Begin();
   while (iter != mutators_stack.End()) {
@@ -570,6 +568,14 @@ void FlutterPlatformViewsController::ApplyMutators(const MutatorsStack& mutators
   embedded_view.layer.transform = flutter::GetCATransform3DFromSkMatrix(transformMatrix);
 }
 
+// Composite the PlatformView with `view_id`.
+//
+// Every frame, during the paint traversal of the layer tree, this method is called for all
+// the PlatformViews in `views_to_recomposite_`.
+//
+// Note that `views_to_recomposite_` does not represent all the views in the view hierarchy,
+// if a PlatformView does not change its composition parameter from last frame, it is not
+// included in the `views_to_recomposite_`.
 void FlutterPlatformViewsController::CompositeWithParams(int64_t view_id,
                                                          const EmbeddedViewParams& params) {
   CGRect frame = CGRectMake(0, 0, params.sizePoints().width(), params.sizePoints().height());

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

@@ -2649,7 +2649,8 @@ fml::RefPtr<fml::TaskRunner> CreateNewThread(std::string name) {
       [[[FlutterClippingMaskViewPool alloc] initWithCapacity:2] autorelease];
   FlutterClippingMaskView* view1 = [pool getMaskViewWithFrame:CGRectZero];
   FlutterClippingMaskView* view2 = [pool getMaskViewWithFrame:CGRectZero];
-  [pool recycleMaskViews];
+  [pool insertViewToPoolIfNeeded:view1];
+  [pool insertViewToPoolIfNeeded:view2];
   CGRect newRect = CGRectMake(0, 0, 10, 10);
   FlutterClippingMaskView* view3 = [pool getMaskViewWithFrame:newRect];
   FlutterClippingMaskView* view4 = [pool getMaskViewWithFrame:newRect];
@@ -2727,10 +2728,6 @@ fml::RefPtr<fml::TaskRunner> CreateNewThread(std::string name) {
   auto embeddedViewParams1 = std::make_unique<flutter::EmbeddedViewParams>(
       screenScaleMatrix, SkSize::Make(10, 10), stack1);
 
-  flutter::MutatorsStack stack2;
-  auto embeddedViewParams2 = std::make_unique<flutter::EmbeddedViewParams>(
-      screenScaleMatrix, SkSize::Make(10, 10), stack2);
-
   flutterPlatformViewsController->PrerollCompositeEmbeddedView(1, std::move(embeddedViewParams1));
   flutterPlatformViewsController->CompositeEmbeddedView(1);
   UIView* childClippingView1 = gMockPlatformView.superview.superview;
@@ -2738,6 +2735,10 @@ fml::RefPtr<fml::TaskRunner> CreateNewThread(std::string name) {
   XCTAssertNotNil(maskView1);
 
   // Composite a new frame.
+  flutterPlatformViewsController->BeginFrame(SkISize::Make(100, 100));
+  flutter::MutatorsStack stack2;
+  auto embeddedViewParams2 = std::make_unique<flutter::EmbeddedViewParams>(
+      screenScaleMatrix, SkSize::Make(10, 10), stack2);
   auto embeddedViewParams3 = std::make_unique<flutter::EmbeddedViewParams>(
       screenScaleMatrix, SkSize::Make(10, 10), stack2);
   flutterPlatformViewsController->PrerollCompositeEmbeddedView(1, std::move(embeddedViewParams3));
@@ -2763,6 +2764,77 @@ fml::RefPtr<fml::TaskRunner> CreateNewThread(std::string name) {
   XCTAssertNil(childClippingView1.maskView);
 }
 
+- (void)testDifferentClipMaskViewIsUsedForEachView {
+  flutter::FlutterPlatformViewsTestMockPlatformViewDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("FlutterPlatformViewsTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto flutterPlatformViewsController = std::make_shared<flutter::FlutterPlatformViewsController>();
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*platform_views_controller=*/flutterPlatformViewsController,
+      /*task_runners=*/runners);
+
+  FlutterPlatformViewsTestMockFlutterPlatformFactory* factory =
+      [[FlutterPlatformViewsTestMockFlutterPlatformFactory new] autorelease];
+  flutterPlatformViewsController->RegisterViewFactory(
+      factory, @"MockFlutterPlatformView",
+      FlutterPlatformViewGestureRecognizersBlockingPolicyEager);
+  FlutterResult result = ^(id result) {
+  };
+
+  flutterPlatformViewsController->OnMethodCall(
+      [FlutterMethodCall
+          methodCallWithMethodName:@"create"
+                         arguments:@{@"id" : @1, @"viewType" : @"MockFlutterPlatformView"}],
+      result);
+  UIView* view1 = gMockPlatformView;
+
+  // This overwrites `gMockPlatformView` to another view.
+  flutterPlatformViewsController->OnMethodCall(
+      [FlutterMethodCall
+          methodCallWithMethodName:@"create"
+                         arguments:@{@"id" : @2, @"viewType" : @"MockFlutterPlatformView"}],
+      result);
+  UIView* view2 = gMockPlatformView;
+
+  XCTAssertNotNil(gMockPlatformView);
+  UIView* mockFlutterView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 10, 10)] autorelease];
+  flutterPlatformViewsController->SetFlutterView(mockFlutterView);
+  // Create embedded view params
+  flutter::MutatorsStack stack1;
+  // Layer tree always pushes a screen scale factor to the stack
+  SkMatrix screenScaleMatrix =
+      SkMatrix::Scale([UIScreen mainScreen].scale, [UIScreen mainScreen].scale);
+  stack1.PushTransform(screenScaleMatrix);
+  // Push a clip rect
+  SkRect rect = SkRect::MakeXYWH(2, 2, 3, 3);
+  stack1.PushClipRect(rect);
+
+  auto embeddedViewParams1 = std::make_unique<flutter::EmbeddedViewParams>(
+      screenScaleMatrix, SkSize::Make(10, 10), stack1);
+
+  flutter::MutatorsStack stack2;
+  stack2.PushClipRect(rect);
+  auto embeddedViewParams2 = std::make_unique<flutter::EmbeddedViewParams>(
+      screenScaleMatrix, SkSize::Make(10, 10), stack2);
+
+  flutterPlatformViewsController->PrerollCompositeEmbeddedView(1, std::move(embeddedViewParams1));
+  flutterPlatformViewsController->CompositeEmbeddedView(1);
+  UIView* childClippingView1 = view1.superview.superview;
+
+  flutterPlatformViewsController->PrerollCompositeEmbeddedView(2, std::move(embeddedViewParams2));
+  flutterPlatformViewsController->CompositeEmbeddedView(2);
+  UIView* childClippingView2 = view2.superview.superview;
+  UIView* maskView1 = childClippingView1.maskView;
+  UIView* maskView2 = childClippingView2.maskView;
+  XCTAssertNotEqual(maskView1, maskView2);
+}
+
 // Return true if a correct visual effect view is found. It also implies all the validation in this
 // method passes.
 //

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

@@ -56,7 +56,7 @@
 // in the pool. If there are none available, a new FlutterClippingMaskView is constructed. If the
 // capacity is reached, the newly constructed FlutterClippingMaskView is not added to the pool.
 //
-// Call |recycleMaskViews| to mark all the FlutterClippingMaskViews in the pool available.
+// Call |insertViewToPoolIfNeeded:| to return a maskView to the pool.
 @interface FlutterClippingMaskViewPool : NSObject
 
 // Initialize the pool with `capacity`. When the `capacity` is reached, a FlutterClippingMaskView is
@@ -66,8 +66,8 @@
 // Reuse a maskView from the pool, or allocate a new one.
 - (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame;
 
-// Mark all the maskViews available.
-- (void)recycleMaskViews;
+// Insert the `maskView` into the pool.
+- (void)insertViewToPoolIfNeeded:(FlutterClippingMaskView*)maskView;
 
 @end
 
@@ -291,20 +291,12 @@ class FlutterPlatformViewsController {
   int CountClips(const MutatorsStack& mutators_stack);
 
   void ClipViewSetMaskView(UIView* clipView);
+
   // Applies the mutators in the mutators_stack to the UIView chain that was constructed by
   // `ReconstructClipViewsChain`
   //
-  // Clips are applied to the super view with a CALayer mask. Transforms are applied to the
-  // current view that's at the head of the chain. For example the following mutators stack [T_1,
-  // C_2, T_3, T_4, C_5, T_6] where T denotes a transform and C denotes a clip, will result in the
-  // following UIView tree:
-  //
-  // C_2 -> C_5 -> PLATFORM_VIEW
-  // (PLATFORM_VIEW is a subview of C_5 which is a subview of C_2)
-  //
-  // T_1 is applied to C_2, T_3 and T_4 are applied to C_5, and T_6 is applied to PLATFORM_VIEW.
-  //
-  // After each clip operation, we update the head to the super view of the current head.
+  // Clips are applied to the `embedded_view`'s super view(|ChildClippingView|) using a
+  // |FlutterClippingMaskView|. Transforms are applied to `embedded_view`
   //
   // The `bounding_rect` is the final bounding rect of the PlatformView
   // (EmbeddedViewParams::finalBoundingRect). If a clip mutator's rect contains the final bounding
@@ -312,6 +304,7 @@ class FlutterPlatformViewsController {
   void ApplyMutators(const MutatorsStack& mutators_stack,
                      UIView* embedded_view,
                      const SkRect& bounding_rect);
+
   void CompositeWithParams(int64_t view_id, const EmbeddedViewParams& params);
 
   // Allocates a new FlutterPlatformViewLayer if needed, draws the pixels within the rect from

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

@@ -9,6 +9,7 @@
 #import "flutter/shell/platform/darwin/ios/ios_surface.h"
 
 static int kMaxPointsInVerb = 4;
+static const NSUInteger kFlutterClippingMaskViewPoolCapacity = 5;
 
 namespace flutter {
 
@@ -26,7 +27,10 @@ FlutterPlatformViewLayer::~FlutterPlatformViewLayer() = default;
 
 FlutterPlatformViewsController::FlutterPlatformViewsController()
     : layer_pool_(std::make_unique<FlutterPlatformViewLayerPool>()),
-      weak_factory_(std::make_unique<fml::WeakPtrFactory<FlutterPlatformViewsController>>(this)){};
+      weak_factory_(std::make_unique<fml::WeakPtrFactory<FlutterPlatformViewsController>>(this)) {
+  mask_view_pool_.reset(
+      [[FlutterClippingMaskViewPool alloc] initWithCapacity:kFlutterClippingMaskViewPoolCapacity]);
+};
 
 FlutterPlatformViewsController::~FlutterPlatformViewsController() = default;
 
@@ -458,9 +462,10 @@ static BOOL _preparedOnce = NO;
 // The maximum number of `FlutterClippingMaskView` the pool can contain.
 // This prevents the pool to grow infinately and limits the maximum memory a pool can use.
 @property(assign, nonatomic) NSUInteger capacity;
-@property(retain, nonatomic) NSMutableArray<FlutterClippingMaskView*>* pool;
-// The index points to the first available FlutterClippingMaskView in the `pool`.
-@property(assign, nonatomic) NSUInteger availableIndex;
+
+// The pool contains the views that are available to use.
+// The number of items in the pool must not excceds `capacity`.
+@property(retain, nonatomic) NSMutableSet<FlutterClippingMaskView*>* pool;
 
 @end
 
@@ -468,48 +473,42 @@ static BOOL _preparedOnce = NO;
 
 - (instancetype)initWithCapacity:(NSInteger)capacity {
   if (self = [super init]) {
-    _pool = [[NSMutableArray alloc] initWithCapacity:capacity];
+    // Most of cases, there are only one PlatformView in the scene.
+    // Thus init with the capacity of 1.
+    _pool = [[NSMutableSet alloc] initWithCapacity:1];
     _capacity = capacity;
-    _availableIndex = 0;
   }
   return self;
 }
 
 - (FlutterClippingMaskView*)getMaskViewWithFrame:(CGRect)frame {
-  FML_DCHECK(self.availableIndex <= self.capacity);
+  FML_DCHECK(self.pool.count <= self.capacity);
   FlutterClippingMaskView* maskView;
-  if (self.availableIndex == self.capacity) {
-    // The pool is full, alloc a new one.
+  if (self.pool.count == 0) {
+    // The pool is empty, alloc a new one.
     maskView =
         [[[FlutterClippingMaskView alloc] initWithFrame:frame
                                             screenScale:[UIScreen mainScreen].scale] autorelease];
     return maskView;
   }
-
-  if (self.availableIndex >= self.pool.count) {
-    // The pool doesn't have enough maskViews, alloc a new one and add to the pool.
-    maskView =
-        [[[FlutterClippingMaskView alloc] initWithFrame:frame
-                                            screenScale:[UIScreen mainScreen].scale] autorelease];
-    [self.pool addObject:maskView];
-    FML_DCHECK(self.pool.count <= self.capacity);
-  } else {
-    // Reuse a maskView from the pool.
-    maskView = [self.pool objectAtIndex:self.availableIndex];
-    maskView.frame = frame;
-    [maskView reset];
-  }
-  self.availableIndex++;
+  maskView = [self.pool anyObject];
+  maskView.frame = frame;
+  [maskView reset];
+  [self.pool removeObject:maskView];
   return maskView;
 }
 
-- (void)recycleMaskViews {
-  self.availableIndex = 0;
+- (void)insertViewToPoolIfNeeded:(FlutterClippingMaskView*)maskView {
+  FML_DCHECK(![self.pool containsObject:maskView]);
+  FML_DCHECK(self.pool.count <= self.capacity);
+  if (self.pool.count == self.capacity) {
+    return;
+  }
+  [self.pool addObject:maskView];
 }
 
 - (void)dealloc {
   [_pool release];
-  _pool = nil;
 
   [super dealloc];
 }

engine/src/flutter/testing/scenario_app/ios/Scenarios/Scenarios.xcodeproj/project.pbxproj

@@ -57,6 +57,9 @@
 		684FFF8D29F9C10700281002 /* golden_platform_view_large_cliprrect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 684FFF7929F9C10600281002 /* golden_platform_view_large_cliprrect_iPhone SE (3rd generation)_16.2_simulator.png */; };
 		684FFF8E29F9C10700281002 /* golden_spawn_engine_works_iPhone SE (3rd generation)_16.2_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 684FFF7A29F9C10700281002 /* golden_spawn_engine_works_iPhone SE (3rd generation)_16.2_simulator.png */; };
 		684FFF8F29F9C10700281002 /* golden_platform_view_with_other_backdrop_filter_iPhone SE (3rd generation)_16.2_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 684FFF7B29F9C10700281002 /* golden_platform_view_with_other_backdrop_filter_iPhone SE (3rd generation)_16.2_simulator.png */; };
+		6860CE252A01B2FF00B68EC5 /* golden_two_platform_view_clip_rrect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6860CE222A01B2FF00B68EC5 /* golden_two_platform_view_clip_rrect_iPhone SE (3rd generation)_16.2_simulator.png */; };
+		6860CE262A01B2FF00B68EC5 /* golden_two_platform_view_clip_rect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6860CE232A01B2FF00B68EC5 /* golden_two_platform_view_clip_rect_iPhone SE (3rd generation)_16.2_simulator.png */; };
+		6860CE272A01B2FF00B68EC5 /* golden_two_platform_view_clip_path_iPhone SE (3rd generation)_16.2_simulator.png in Resources */ = {isa = PBXBuildFile; fileRef = 6860CE242A01B2FF00B68EC5 /* golden_two_platform_view_clip_path_iPhone SE (3rd generation)_16.2_simulator.png */; };
 		68A5B63423EB71D300BDBCDB /* PlatformViewGestureRecognizerTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 68A5B63323EB71D300BDBCDB /* PlatformViewGestureRecognizerTests.m */; };
 		68D4017D2564859300ECD91A /* ContinuousTexture.m in Sources */ = {isa = PBXBuildFile; fileRef = 68D4017C2564859300ECD91A /* ContinuousTexture.m */; };
 		F26F15B8268B6B5600EC54D3 /* iPadGestureTests.m in Sources */ = {isa = PBXBuildFile; fileRef = F26F15B7268B6B5500EC54D3 /* iPadGestureTests.m */; };
@@ -174,6 +177,9 @@
 		684FFF7929F9C10600281002 /* golden_platform_view_large_cliprrect_iPhone SE (3rd generation)_16.2_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_large_cliprrect_iPhone SE (3rd generation)_16.2_simulator.png"; sourceTree = "<group>"; };
 		684FFF7A29F9C10700281002 /* golden_spawn_engine_works_iPhone SE (3rd generation)_16.2_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_spawn_engine_works_iPhone SE (3rd generation)_16.2_simulator.png"; sourceTree = "<group>"; };
 		684FFF7B29F9C10700281002 /* golden_platform_view_with_other_backdrop_filter_iPhone SE (3rd generation)_16.2_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_platform_view_with_other_backdrop_filter_iPhone SE (3rd generation)_16.2_simulator.png"; sourceTree = "<group>"; };
+		6860CE222A01B2FF00B68EC5 /* golden_two_platform_view_clip_rrect_iPhone SE (3rd generation)_16.2_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_two_platform_view_clip_rrect_iPhone SE (3rd generation)_16.2_simulator.png"; sourceTree = "<group>"; };
+		6860CE232A01B2FF00B68EC5 /* golden_two_platform_view_clip_rect_iPhone SE (3rd generation)_16.2_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_two_platform_view_clip_rect_iPhone SE (3rd generation)_16.2_simulator.png"; sourceTree = "<group>"; };
+		6860CE242A01B2FF00B68EC5 /* golden_two_platform_view_clip_path_iPhone SE (3rd generation)_16.2_simulator.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "golden_two_platform_view_clip_path_iPhone SE (3rd generation)_16.2_simulator.png"; sourceTree = "<group>"; };
 		68A5B63323EB71D300BDBCDB /* PlatformViewGestureRecognizerTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = PlatformViewGestureRecognizerTests.m; sourceTree = "<group>"; };
 		68D4017B2564859300ECD91A /* ContinuousTexture.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = ContinuousTexture.h; sourceTree = "<group>"; };
 		68D4017C2564859300ECD91A /* ContinuousTexture.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = ContinuousTexture.m; sourceTree = "<group>"; };
@@ -302,6 +308,9 @@
 		F7B464DC2759D02B00079189 /* Goldens */ = {
 			isa = PBXGroup;
 			children = (
+				6860CE242A01B2FF00B68EC5 /* golden_two_platform_view_clip_path_iPhone SE (3rd generation)_16.2_simulator.png */,
+				6860CE232A01B2FF00B68EC5 /* golden_two_platform_view_clip_rect_iPhone SE (3rd generation)_16.2_simulator.png */,
+				6860CE222A01B2FF00B68EC5 /* golden_two_platform_view_clip_rrect_iPhone SE (3rd generation)_16.2_simulator.png */,
 				684FFF7229F9C10500281002 /* golden_bogus_font_text_iPhone SE (3rd generation)_16.2_simulator.png */,
 				684FFF7029F9C10500281002 /* golden_non_full_screen_flutter_view_platform_view_iPhone SE (3rd generation)_16.2_simulator.png */,
 				684FFF7729F9C10600281002 /* golden_platform_view_clippath_iPhone SE (3rd generation)_16.2_simulator.png */,
@@ -456,7 +465,9 @@
 				684FFF7D29F9C10700281002 /* golden_platform_view_cliprect_with_transform_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8829F9C10700281002 /* golden_platform_view_cliprect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8529F9C10700281002 /* golden_platform_view_cliprrect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
+				6860CE252A01B2FF00B68EC5 /* golden_two_platform_view_clip_rrect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8F29F9C10700281002 /* golden_platform_view_with_other_backdrop_filter_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
+				6860CE262A01B2FF00B68EC5 /* golden_two_platform_view_clip_rect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8A29F9C10700281002 /* golden_platform_view_clippath_with_transform_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8429F9C10700281002 /* golden_non_full_screen_flutter_view_platform_view_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF7C29F9C10700281002 /* golden_platform_view_cliprrect_with_transform_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
@@ -469,6 +480,7 @@
 				684FFF8D29F9C10700281002 /* golden_platform_view_large_cliprrect_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8329F9C10700281002 /* golden_platform_view_transform_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8B29F9C10700281002 /* golden_platform_view_clippath_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
+				6860CE272A01B2FF00B68EC5 /* golden_two_platform_view_clip_path_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 				684FFF8129F9C10700281002 /* golden_platform_view_large_cliprrect_with_transform_iPhone SE (3rd generation)_16.2_simulator.png in Resources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;

engine/src/flutter/testing/scenario_app/ios/Scenarios/Scenarios/AppDelegate.m

@@ -69,7 +69,10 @@
     @"--spawn-engine-works" : @"spawn_engine_works",
     @"--pointer-events" : @"pointer_events",
     @"--platform-view-scrolling-under-widget" : @"platform_view_scrolling_under_widget",
-    @"--platform-view-cliprect-after-moved" : @"platform_view_cliprect_after_moved"
+    @"--platform-view-cliprect-after-moved" : @"platform_view_cliprect_after_moved",
+    @"--two-platform-view-clip-rect" : @"two_platform_view_clip_rect",
+    @"--two-platform-view-clip-rrect" : @"two_platform_view_clip_rrect",
+    @"--two-platform-view-clip-path" : @"two_platform_view_clip_path",
   };
   __block NSString* flutterViewControllerTestName = nil;
   [launchArgsMap

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/GoldenTestManager.m

@@ -47,6 +47,9 @@ NSDictionary* launchArgsMap;
         @"--bogus-font-text" : @"bogus_font_text",
         @"--spawn-engine-works" : @"spawn_engine_works",
         @"--platform-view-cliprect-after-moved" : @"platform_view_cliprect_after_moved",
+        @"--two-platform-view-clip-rect" : @"two_platform_view_clip_rect",
+        @"--two-platform-view-clip-rrect" : @"two_platform_view_clip_rrect",
+        @"--two-platform-view-clip-path" : @"two_platform_view_clip_path",
       };
     });
     _identifier = launchArgsMap[launchArg];

engine/src/flutter/testing/scenario_app/ios/Scenarios/ScenariosUITests/PlatformViewUITests.m

@@ -254,6 +254,60 @@ static const NSInteger kSecondsToWaitForPlatformView = 30;
 
 @end
 
+@interface TwoPlatformViewClipRectTests : GoldenPlatformViewTests
+
+@end
+
+@implementation TwoPlatformViewClipRectTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  GoldenTestManager* manager =
+      [[GoldenTestManager alloc] initWithLaunchArg:@"--two-platform-view-clip-rect"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkPlatformViewGolden];
+}
+
+@end
+
+@interface TwoPlatformViewClipRRectTests : GoldenPlatformViewTests
+
+@end
+
+@implementation TwoPlatformViewClipRRectTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  GoldenTestManager* manager =
+      [[GoldenTestManager alloc] initWithLaunchArg:@"--two-platform-view-clip-rrect"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkPlatformViewGolden];
+}
+
+@end
+
+@interface TwoPlatformViewClipPathTests : GoldenPlatformViewTests
+
+@end
+
+@implementation TwoPlatformViewClipPathTests
+
+- (instancetype)initWithInvocation:(NSInvocation*)invocation {
+  GoldenTestManager* manager =
+      [[GoldenTestManager alloc] initWithLaunchArg:@"--two-platform-view-clip-path"];
+  return [super initWithManager:manager invocation:invocation];
+}
+
+- (void)testPlatformView {
+  [self checkPlatformViewGolden];
+}
+
+@end
+
 @interface PlatformViewMutationTransformTests : GoldenPlatformViewTests
 
 @end

engine/src/flutter/testing/scenario_app/lib/src/platform_view.dart

@@ -112,7 +112,6 @@ class PlatformViewNoOverlayIntersectionScenario extends Scenario
   }
 }
 
-
 /// A platform view that is larger than the display size.
 /// This is only applicable on Android while using virtual displays.
 /// Related issue: https://github.com/flutter/flutter/issues/28978.
@@ -576,7 +575,7 @@ class PlatformViewClipRectAfterMovedScenario extends Scenario with _BasePlatform
       ..pushClipRect(const Rect.fromLTRB(100, 100, 400, 400));
 
     addPlatformView(
-      _numberOfFrames == 10? 10000:id,
+      _numberOfFrames == 10? 10000: id,
       dispatcher: view.platformDispatcher,
       sceneBuilder: builder,
     );
@@ -639,7 +638,6 @@ class PlatformViewClipRRectScenario extends PlatformViewScenario {
   }
 }
 
-
 /// Platform view with clip rrect.
 /// The bounding rect of the rrect is the same as PlatformView and only the corner radii clips the PlatformView.
 class PlatformViewLargeClipRRectScenario extends PlatformViewScenario {
@@ -878,6 +876,187 @@ class PlatformViewClipPathWithTransformScenario extends PlatformViewScenario {
   }
 }
 
+/// Two platform views, both have clip rects
+class TwoPlatformViewClipRect extends Scenario
+    with _BasePlatformViewScenarioMixin {
+  /// Creates the PlatformView scenario.
+  TwoPlatformViewClipRect(
+    super.view, {
+    required this.firstId,
+    required this.secondId,
+  });
+
+  /// The platform view identifier to use for the first platform view.
+  final int firstId;
+
+  /// The platform view identifier to use for the second platform view.
+  final int secondId;
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+    builder.pushOffset(0, 600);
+    builder.pushClipRect(const Rect.fromLTRB(100, 100, 400, 400));
+
+    addPlatformView(
+      firstId,
+      dispatcher: view.platformDispatcher,
+      sceneBuilder: builder,
+      text: 'platform view 1',
+    );
+
+    builder.pop();
+    builder.pop();
+
+    // Use a different rect to differentiate from the 1st clip rect.
+    builder.pushClipRect(const Rect.fromLTRB(100, 100, 300, 300));
+
+    addPlatformView(
+      secondId,
+      dispatcher: view.platformDispatcher,
+      sceneBuilder: builder,
+      text: 'platform view 2',
+    );
+
+    builder.pop();
+    final Scene scene = builder.build();
+    view.render(scene);
+    scene.dispose();
+  }
+}
+
+/// Two platform views, both have clip rrects
+class TwoPlatformViewClipRRect extends Scenario
+    with _BasePlatformViewScenarioMixin {
+  /// Creates the PlatformView scenario.
+  TwoPlatformViewClipRRect(
+    super.view, {
+    required this.firstId,
+    required this.secondId,
+  });
+
+  /// The platform view identifier to use for the first platform view.
+  final int firstId;
+
+  /// The platform view identifier to use for the second platform view.
+  final int secondId;
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+    builder.pushOffset(0, 600);
+    builder.pushClipRRect(
+      RRect.fromLTRBAndCorners(
+        0,
+        0,
+        500,
+        500,
+        topLeft: const Radius.circular(15),
+        topRight: const Radius.circular(50),
+        bottomLeft: const Radius.circular(50),
+      ),
+    );
+
+    addPlatformView(
+      firstId,
+      dispatcher: view.platformDispatcher,
+      sceneBuilder: builder,
+      text: 'platform view 1',
+    );
+
+    builder.pop();
+    builder.pop();
+
+    // Use a different rrect to differentiate from the 1st clip rrect.
+    builder.pushClipRRect(
+      RRect.fromLTRBAndCorners(
+        0,
+        0,
+        500,
+        500,
+        topLeft: const Radius.circular(100),
+        topRight: const Radius.circular(50),
+        bottomLeft: const Radius.circular(50),
+      ),
+    );
+
+    addPlatformView(
+      secondId,
+      dispatcher: view.platformDispatcher,
+      sceneBuilder: builder,
+      text: 'platform view 2',
+    );
+
+    builder.pop();
+    final Scene scene = builder.build();
+    view.render(scene);
+    scene.dispose();
+  }
+}
+
+/// Two platform views, both have clip path
+class TwoPlatformViewClipPath extends Scenario
+    with _BasePlatformViewScenarioMixin {
+  /// Creates the PlatformView scenario.
+  TwoPlatformViewClipPath(
+    super.view, {
+    required this.firstId,
+    required this.secondId,
+  });
+
+  /// The platform view identifier to use for the first platform view.
+  final int firstId;
+
+  /// The platform view identifier to use for the second platform view.
+  final int secondId;
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final SceneBuilder builder = SceneBuilder();
+    builder.pushOffset(0, 600);
+    final Path path = Path()
+      ..moveTo(100, 100)
+      ..quadraticBezierTo(50, 250, 100, 400)
+      ..lineTo(350, 400)
+      ..cubicTo(400, 300, 300, 200, 350, 100)
+      ..close();
+
+    builder.pushClipPath(path);
+
+    addPlatformView(
+      firstId,
+      dispatcher: view.platformDispatcher,
+      sceneBuilder: builder,
+      text: 'platform view 1',
+    );
+
+    builder.pop();
+    builder.pop();
+
+    // Use a different path to differentiate from the 1st clip path.
+    final Path path2 = Path()
+      ..moveTo(100, 100)
+      ..quadraticBezierTo(100, 150, 100, 400)
+      ..lineTo(350, 350)
+      ..cubicTo(400, 300, 300, 200, 350, 200)
+      ..close();
+
+    builder.pushClipPath(path2);
+
+    addPlatformView(
+      secondId,
+      dispatcher: view.platformDispatcher,
+      sceneBuilder: builder,
+      text: 'platform view 2',
+    );
+
+    builder.pop();
+    final Scene scene = builder.build();
+    view.render(scene);
+    scene.dispose();
+  }
+}
+
 /// Platform view with transform.
 class PlatformViewTransformScenario extends PlatformViewScenario {
   /// Constructs a platform view with transform scenario.
@@ -1044,10 +1223,10 @@ class PlatformViewForOverlappingPlatformViewsScenario extends Scenario
 
   /// Creates the PlatformViewForOverlappingPlatformViewsScenario.
   PlatformViewForOverlappingPlatformViewsScenario(
-      super.view, {
-        required this.foregroundId,
-        required this.backgroundId,
-      }) {
+    super.view, {
+    required this.foregroundId,
+    required this.backgroundId,
+  }) {
     _nextFrame = _firstFrame;
   }
 
@@ -1151,7 +1330,7 @@ class PlatformViewForOverlappingPlatformViewsScenario extends Scenario
       view.platformDispatcher.sendPlatformMessage(
         'flutter/platform_views',
         message.buffer.asByteData(),
-            (ByteData? response) {},
+        (ByteData? response) {},
       );
     }
   }
@@ -1360,7 +1539,7 @@ class PlatformViewScrollingUnderWidget extends Scenario
     super.view, {
     required int firstPlatformViewId,
     required int lastPlatformViewId,
-  }) : _firstPlatformViewId = firstPlatformViewId,
+  }) :  _firstPlatformViewId = firstPlatformViewId,
        _lastPlatformViewId = lastPlatformViewId;
 
   final int _firstPlatformViewId;
@@ -1450,7 +1629,6 @@ void addPlatformView(
   }
 
   final String platformViewKey = '$viewType-$id';
-
   if (_createdPlatformViews.containsKey(platformViewKey)) {
     addPlatformViewToSceneBuilder(
       id,
@@ -1473,7 +1651,6 @@ void addPlatformView(
   const int valueString = 7;
   const int valueUint8List = 8;
   const int valueMap = 13;
-
   final Uint8List message = Uint8List.fromList(<int>[
     valueString,
     ..._encodeString('create'),

engine/src/flutter/testing/scenario_app/lib/src/scenarios.dart

@@ -53,6 +53,9 @@ Map<String, _ScenarioFactory> _scenarios = <String, _ScenarioFactory>{
   'platform_view_gesture_reject_after_touches_ended': (FlutterView view) => PlatformViewForTouchIOSScenario(view, id: _viewId++, accept: false, rejectUntilTouchesEnded: true),
   'platform_view_gesture_accept_with_overlapping_platform_views': (FlutterView view) => PlatformViewForOverlappingPlatformViewsScenario(view, foregroundId: _viewId++, backgroundId: _viewId++),
   'platform_view_scrolling_under_widget':(FlutterView view) => PlatformViewScrollingUnderWidget(view, firstPlatformViewId: _viewId++, lastPlatformViewId: _viewId+=16),
+  'two_platform_view_clip_rect': (FlutterView view) => TwoPlatformViewClipRect(view, firstId: _viewId++, secondId: _viewId++),
+  'two_platform_view_clip_rrect': (FlutterView view) => TwoPlatformViewClipRRect(view, firstId: _viewId++, secondId: _viewId++),
+  'two_platform_view_clip_path': (FlutterView view) => TwoPlatformViewClipPath(view, firstId: _viewId++, secondId: _viewId++),
   'tap_status_bar': (FlutterView view) => TouchesScenario(view),
   'initial_route_reply': (FlutterView view) => InitialRouteReply(view),
   'platform_view_with_continuous_texture': (FlutterView view) => PlatformViewWithContinuousTexture(view, id: _viewId++),