From 27b415ec593457e50c4c4c90f31ecc348084e359 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 23 Sep 2022 14:33:37 -0700
Subject: [PATCH 01/10] Impl

---
 .../framework/Source/FlutterCompositor.h      | 10 ++++--
 .../framework/Source/FlutterCompositor.mm     | 18 ++++++----
 .../macos/framework/Source/FlutterEngine.mm   | 18 ++++++----
 .../framework/Source/FlutterGLCompositor.h    |  2 +-
 .../framework/Source/FlutterGLCompositor.mm   | 10 +++---
 .../Source/FlutterGLCompositorUnittests.mm    |  8 +++--
 .../framework/Source/FlutterMetalCompositor.h |  9 +++--
 .../Source/FlutterMetalCompositor.mm          | 25 ++++++++-----
 .../Source/FlutterMetalCompositorUnittests.mm | 36 ++++++++++++-------
 9 files changed, 89 insertions(+), 47 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
index 141e27509dd44..99431f1a5378f 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
@@ -9,7 +9,7 @@
 #include <list>
 
 #include "flutter/fml/macros.h"
-#include "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewController_Internal.h"
+#include "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
 #include "flutter/shell/platform/embedder/embedder.h"
 
 namespace flutter {
@@ -19,7 +19,9 @@ namespace flutter {
 // Platform views are not yet supported.
 class FlutterCompositor {
  public:
-  explicit FlutterCompositor(FlutterViewController* view_controller);
+  using GetViewCallback = std::function<FlutterView*(uint64_t view_id)>;
+
+  explicit FlutterCompositor(GetViewCallback get_view_callback);
 
   virtual ~FlutterCompositor() = default;
 
@@ -62,7 +64,7 @@ class FlutterCompositor {
   typedef enum { kStarted, kPresenting, kEnded } FrameStatus;
 
  protected:
-  __weak const FlutterViewController* view_controller_;
+  FlutterView* GetView(uint64_t view_id);
 
   // Gets and sets the FrameStatus for the current frame.
   void SetFrameStatus(FrameStatus frame_status);
@@ -85,6 +87,8 @@ class FlutterCompositor {
   // A list of the active CALayer objects for the frame that need to be removed.
   std::list<CALayer*> active_ca_layers_;
 
+  GetViewCallback get_view_callback_;
+
   // Callback set by the embedder to be called when the layer tree has been
   // correctly set up for this frame.
   PresentCallback present_callback_;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
index 3015a716c6ca6..c18a589c55855 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
@@ -7,10 +7,8 @@
 
 namespace flutter {
 
-FlutterCompositor::FlutterCompositor(FlutterViewController* view_controller) {
-  FML_CHECK(view_controller != nullptr) << "FlutterViewController* cannot be nullptr";
-
-  view_controller_ = view_controller;
+FlutterCompositor::FlutterCompositor(GetViewCallback get_view_callback) {
+  get_view_callback_ = std::move(get_view_callback);
 }
 
 void FlutterCompositor::SetPresentCallback(
@@ -35,6 +33,10 @@
   return status;
 }
 
+FlutterView* FlutterCompositor::GetView(uint64_t view_id) {
+  return get_view_callback_(view_id);
+}
+
 void FlutterCompositor::SetFrameStatus(FlutterCompositor::FrameStatus frame_status) {
   frame_status_ = frame_status;
 }
@@ -45,12 +47,16 @@
 
 void FlutterCompositor::InsertCALayerForIOSurface(const IOSurfaceRef& io_surface,
                                                   CATransform3D transform) {
+  FlutterView* view = GetView(0);
+  if (!view) {
+    return;
+  }
   // FlutterCompositor manages the lifecycle of CALayers.
   CALayer* content_layer = [[CALayer alloc] init];
   content_layer.transform = transform;
-  content_layer.frame = view_controller_.flutterView.layer.bounds;
+  content_layer.frame = view.layer.bounds;
   [content_layer setContents:(__bridge id)io_surface];
-  [view_controller_.flutterView.layer addSublayer:content_layer];
+  [view.layer addSublayer:content_layer];
 
   active_ca_layers_.push_back(content_layer);
 }
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index f638e0fe79578..339d8f8a2a7ee 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -428,16 +428,22 @@ - (FlutterCompositor*)createFlutterCompositor {
   // TODO(richardjcai): Add support for creating a FlutterCompositor
   // with a nil _viewController for headless engines.
   // https://github.com/flutter/flutter/issues/71606
-  if (!_viewController) {
+  FlutterViewController* viewController = _viewController;
+  if (!viewController) {
     return nil;
   }
 
   __weak FlutterEngine* weakSelf = self;
 
+  flutter::FlutterCompositor::GetViewCallback get_view_callback =
+      [&viewController](uint64_t view_id) {
+        return viewController == nullptr ? nullptr : viewController.flutterView;
+      };
+
   if ([FlutterRenderingBackend renderUsingMetal]) {
     FlutterMetalRenderer* metalRenderer = reinterpret_cast<FlutterMetalRenderer*>(_renderer);
     _macOSCompositor = std::make_unique<flutter::FlutterMetalCompositor>(
-        _viewController, _platformViewController, metalRenderer.device);
+        std::move(get_view_callback), _platformViewController, metalRenderer.device);
     _macOSCompositor->SetPresentCallback([weakSelf](bool has_flutter_content) {
       FlutterMetalRenderer* metalRenderer =
           reinterpret_cast<FlutterMetalRenderer*>(weakSelf.renderer);
@@ -451,7 +457,7 @@ - (FlutterCompositor*)createFlutterCompositor {
   } else {
     FlutterOpenGLRenderer* openGLRenderer = reinterpret_cast<FlutterOpenGLRenderer*>(_renderer);
     [openGLRenderer.openGLContext makeCurrentContext];
-    _macOSCompositor = std::make_unique<flutter::FlutterGLCompositor>(_viewController,
+    _macOSCompositor = std::make_unique<flutter::FlutterGLCompositor>(std::move(get_view_callback),
                                                                       openGLRenderer.openGLContext);
 
     _macOSCompositor->SetPresentCallback([weakSelf](bool has_flutter_content) {
@@ -645,9 +651,9 @@ - (void)sendUserLocales {
   // Convert to a list of pointers, and send to the engine.
   std::vector<const FlutterLocale*> flutterLocaleList;
   flutterLocaleList.reserve(flutterLocales.size());
-  std::transform(
-      flutterLocales.begin(), flutterLocales.end(), std::back_inserter(flutterLocaleList),
-      [](const auto& arg) -> const auto* { return &arg; });
+  std::transform(flutterLocales.begin(), flutterLocales.end(),
+                 std::back_inserter(flutterLocaleList),
+                 [](const auto& arg) -> const auto* { return &arg; });
   _embedderAPI.UpdateLocales(_engine, flutterLocaleList.data(), flutterLocaleList.size());
 }
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
index 385099a66d1b5..24abfc2eda3fc 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
@@ -19,7 +19,7 @@ namespace flutter {
 // FlutterGLCompositor is created and destroyed by FlutterEngine.
 class FlutterGLCompositor : public FlutterCompositor {
  public:
-  FlutterGLCompositor(FlutterViewController* view_controller,
+  FlutterGLCompositor(GetViewCallback get_view_callback,
                       NSOpenGLContext* opengl_context);
 
   virtual ~FlutterGLCompositor() = default;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index c8c6ce7f93056..187152160669f 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -19,13 +19,14 @@
 
 namespace flutter {
 
-FlutterGLCompositor::FlutterGLCompositor(FlutterViewController* view_controller,
+FlutterGLCompositor::FlutterGLCompositor(GetViewCallback get_view_callback,
                                          NSOpenGLContext* opengl_context)
-    : FlutterCompositor(view_controller), open_gl_context_(opengl_context) {}
+    : FlutterCompositor(get_view_callback), open_gl_context_(opengl_context) {}
 
 bool FlutterGLCompositor::CreateBackingStore(const FlutterBackingStoreConfig* config,
                                              FlutterBackingStore* backing_store_out) {
-  if (!view_controller_) {
+  FlutterView* view = GetView(0);
+  if (!view) {
     return false;
   }
 
@@ -36,8 +37,7 @@
     // If the backing store is for the first layer, return the fbo for the
     // FlutterView.
     FlutterOpenGLRenderBackingStore* backingStore =
-        reinterpret_cast<FlutterOpenGLRenderBackingStore*>(
-            [view_controller_.flutterView backingStoreForSize:size]);
+        reinterpret_cast<FlutterOpenGLRenderBackingStore*>([view backingStoreForSize:size]);
     backing_store_out->open_gl.framebuffer.name = backingStore.frameBufferID;
   } else {
     FlutterFrameBufferProvider* fb_provider =
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
index 93e76ea5f251d..2a9da0e49072a 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #import <Foundation/Foundation.h>
+#import <OCMock/OCMock.h>
 
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewControllerTestUtils.h"
@@ -11,10 +12,13 @@
 namespace flutter::testing {
 
 TEST(FlutterGLCompositorTest, TestPresent) {
-  id mockViewController = CreateMockViewController();
+  id mock_view = OCMClassMock([FlutterView class]);
+  flutter::FlutterCompositor::GetViewCallback get_view_callback = [&mock_view](uint64_t view_id) {
+    return mock_view;
+  };
 
   std::unique_ptr<flutter::FlutterGLCompositor> macos_compositor =
-      std::make_unique<FlutterGLCompositor>(mockViewController, nullptr);
+      std::make_unique<FlutterGLCompositor>(get_view_callback, nullptr);
 
   bool flag = false;
   macos_compositor->SetPresentCallback([f = &flag](bool has_flutter_content) {
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
index 84e67710fc445..1c142673a6e1e 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
@@ -14,7 +14,7 @@ namespace flutter {
 class FlutterMetalCompositor : public FlutterCompositor {
  public:
   explicit FlutterMetalCompositor(
-      FlutterViewController* view_controller,
+      GetViewCallback get_view_callback,
       FlutterPlatformViewController* platform_views_controller,
       id<MTLDevice> mtl_device);
 
@@ -46,8 +46,11 @@ class FlutterMetalCompositor : public FlutterCompositor {
 
  private:
   // Presents the platform view layer represented by `layer`. `layer_index` is
-  // used to position the layer in the z-axis.
-  void PresentPlatformView(const FlutterLayer* layer, size_t layer_index);
+  // used to position the layer in the z-axis. If the layer does not have a
+  // superview, it will become subview of `default_super_view`.
+  void PresentPlatformView(FlutterView* default_super_view,
+                           const FlutterLayer* layer,
+                           size_t layer_position);
 
   const id<MTLDevice> mtl_device_;
   const FlutterPlatformViewController* platform_views_controller_;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index e1bcf9bab1f6b..824e66044d049 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -11,16 +11,17 @@
 namespace flutter {
 
 FlutterMetalCompositor::FlutterMetalCompositor(
-    FlutterViewController* view_controller,
+    GetViewCallback get_view_callback,
     FlutterPlatformViewController* platform_views_controller,
     id<MTLDevice> mtl_device)
-    : FlutterCompositor(view_controller),
+    : FlutterCompositor(get_view_callback),
       mtl_device_(mtl_device),
       platform_views_controller_(platform_views_controller) {}
 
 bool FlutterMetalCompositor::CreateBackingStore(const FlutterBackingStoreConfig* config,
                                                 FlutterBackingStore* backing_store_out) {
-  if (!view_controller_) {
+  FlutterView* view = GetView(0);
+  if (!view) {
     return false;
   }
 
@@ -34,8 +35,7 @@
     // If the backing store is for the first layer, return the MTLTexture for the
     // FlutterView.
     FlutterMetalRenderBackingStore* backingStore =
-        reinterpret_cast<FlutterMetalRenderBackingStore*>(
-            [view_controller_.flutterView backingStoreForSize:size]);
+        reinterpret_cast<FlutterMetalRenderBackingStore*>([view backingStoreForSize:size]);
     backing_store_out->metal.texture.texture =
         (__bridge FlutterMetalTextureHandle)backingStore.texture;
   } else {
@@ -96,16 +96,23 @@
         has_flutter_content = true;
         break;
       }
-      case kFlutterLayerContentTypePlatformView:
-        PresentPlatformView(layer, i);
+      case kFlutterLayerContentTypePlatformView: {
+        FlutterView* view = GetView(0);
+        if (!view) {
+          return false;
+        }
+        PresentPlatformView(view, layer, i);
         break;
+      }
     };
   }
 
   return EndFrame(has_flutter_content);
 }
 
-void FlutterMetalCompositor::PresentPlatformView(const FlutterLayer* layer, size_t layer_position) {
+void FlutterMetalCompositor::PresentPlatformView(FlutterView* default_super_view,
+                                                 const FlutterLayer* layer,
+                                                 size_t layer_position) {
   // TODO (https://github.com/flutter/flutter/issues/96668)
   // once the issue is fixed, this check will pass.
   FML_DCHECK([[NSThread currentThread] isMainThread])
@@ -120,7 +127,7 @@
   platform_view.frame = CGRectMake(layer->offset.x / scale, layer->offset.y / scale,
                                    layer->size.width / scale, layer->size.height / scale);
   if (platform_view.superview == nil) {
-    [view_controller_.flutterView addSubview:platform_view];
+    [default_super_view addSubview:platform_view];
   }
   platform_view.layer.zPosition = layer_position;
 }
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
index ac0e0330405bd..531c85fc1a047 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
@@ -3,19 +3,37 @@
 // found in the LICENSE file.
 
 #import <Foundation/Foundation.h>
+#import <OCMock/OCMock.h>
 
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h"
-#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterViewControllerTestUtils.h"
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
 #import "flutter/testing/testing.h"
 
 namespace flutter::testing {
 
-TEST(FlutterMetalCompositorTest, TestPresent) {
-  id mockViewController = CreateMockViewController();
+flutter::FlutterCompositor::GetViewCallback MockGetViewCallback() {
+  FlutterView* viewMock = OCMClassMock([FlutterView class]);
+  FlutterMetalRenderBackingStore* backingStoreMock =
+      OCMClassMock([FlutterMetalRenderBackingStore class]);
+  __block id<MTLTexture> textureMock = OCMProtocolMock(@protocol(MTLTexture));
+  OCMStub([backingStoreMock texture]).andReturn(textureMock);
+
+  OCMStub([viewMock backingStoreForSize:CGSize{}])
+      .ignoringNonObjectArgs()
+      .andDo(^(NSInvocation* invocation) {
+        CGSize size;
+        [invocation getArgument:&size atIndex:2];
+        OCMStub([textureMock width]).andReturn(size.width);
+        OCMStub([textureMock height]).andReturn(size.height);
+      })
+      .andReturn(backingStoreMock);
+  return [viewMock](uint64_t view_id) { return viewMock; };
+}
 
+TEST(FlutterMetalCompositorTest, TestPresent) {
   std::unique_ptr<flutter::FlutterMetalCompositor> macos_compositor =
       std::make_unique<FlutterMetalCompositor>(
-          mockViewController, /*platform_view_controller*/ nullptr, /*mtl_device*/ nullptr);
+          MockGetViewCallback(), /*platform_view_controller*/ nullptr, /*mtl_device*/ nullptr);
 
   bool flag = false;
   macos_compositor->SetPresentCallback([f = &flag](bool has_flutter_content) {
@@ -28,12 +46,9 @@
 }
 
 TEST(FlutterMetalCompositorTest, TestCreate) {
-  id mockViewController = CreateMockViewController();
-  [mockViewController loadView];
-
   std::unique_ptr<flutter::FlutterMetalCompositor> macos_compositor =
       std::make_unique<FlutterMetalCompositor>(
-          mockViewController, /*platform_view_controller*/ nullptr, /*mtl_device*/ nullptr);
+          MockGetViewCallback(), /*platform_view_controller*/ nullptr, /*mtl_device*/ nullptr);
 
   FlutterBackingStore backing_store;
   FlutterBackingStoreConfig config;
@@ -50,12 +65,9 @@
 }
 
 TEST(FlutterMetalCompositorTest, TestCompositing) {
-  id mockViewController = CreateMockViewController();
-  [mockViewController loadView];
-
   std::unique_ptr<flutter::FlutterMetalCompositor> macos_compositor =
       std::make_unique<FlutterMetalCompositor>(
-          mockViewController, /*platform_view_controller*/ nullptr, /*mtl_device*/ nullptr);
+          MockGetViewCallback(), /*platform_view_controller*/ nullptr, /*mtl_device*/ nullptr);
 
   FlutterBackingStore backing_store;
   FlutterBackingStoreConfig config;

From 7c4676fd01037966ef55441a7b8b13caf0f5051c Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 23 Sep 2022 14:49:06 -0700
Subject: [PATCH 02/10] Explain 0

---
 .../darwin/macos/framework/Source/FlutterCompositor.mm        | 2 ++
 .../darwin/macos/framework/Source/FlutterGLCompositor.mm      | 2 ++
 .../darwin/macos/framework/Source/FlutterMetalCompositor.mm   | 4 ++++
 3 files changed, 8 insertions(+)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
index c18a589c55855..7d6c93f7c754f 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
@@ -47,6 +47,8 @@
 
 void FlutterCompositor::InsertCALayerForIOSurface(const IOSurfaceRef& io_surface,
                                                   CATransform3D transform) {
+  // Always gets the first view, #0. After Flutter supports multi-view, it
+  // should get the view ID from somewhere.
   FlutterView* view = GetView(0);
   if (!view) {
     return;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index 187152160669f..6969118d6aa80 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -25,6 +25,8 @@
 
 bool FlutterGLCompositor::CreateBackingStore(const FlutterBackingStoreConfig* config,
                                              FlutterBackingStore* backing_store_out) {
+  // Always gets the first view, #0. After Flutter supports multi-view, it
+  // should get the view ID from somewhere.
   FlutterView* view = GetView(0);
   if (!view) {
     return false;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index 824e66044d049..34b60da002a5a 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -20,6 +20,8 @@
 
 bool FlutterMetalCompositor::CreateBackingStore(const FlutterBackingStoreConfig* config,
                                                 FlutterBackingStore* backing_store_out) {
+  // Always gets the first view, #0. After Flutter supports multi-view, it
+  // should get the view ID from somewhere.
   FlutterView* view = GetView(0);
   if (!view) {
     return false;
@@ -97,6 +99,8 @@
         break;
       }
       case kFlutterLayerContentTypePlatformView: {
+        // Always gets the first view, #0. After Flutter supports multi-view, it
+        // should get the view ID from somewhere.
         FlutterView* view = GetView(0);
         if (!view) {
           return false;

From 954c501a42f28b3fb9e552c802bd0d75adec6ebe Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 23 Sep 2022 16:48:29 -0700
Subject: [PATCH 03/10] InsertCALayerForIOSurface use view

---
 .../macos/framework/Source/FlutterCompositor.h    |  3 ++-
 .../macos/framework/Source/FlutterCompositor.mm   |  9 ++-------
 .../framework/Source/FlutterMetalCompositor.mm    | 15 ++++++++-------
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
index 99431f1a5378f..6999be7e54b73 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
@@ -78,8 +78,9 @@ class FlutterCompositor {
   bool EndFrame(bool has_flutter_content);
 
   // Creates a CALayer object which is backed by the supplied IOSurface, and
-  // adds it to the root CALayer for this FlutterViewController's view.
+  // adds it to the root CALayer for the given view.
   void InsertCALayerForIOSurface(
+      FlutterView* view,
       const IOSurfaceRef& io_surface,
       CATransform3D transform = CATransform3DIdentity);
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
index 7d6c93f7c754f..cf3fcc478268c 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
@@ -45,14 +45,9 @@
   return frame_status_;
 }
 
-void FlutterCompositor::InsertCALayerForIOSurface(const IOSurfaceRef& io_surface,
+void FlutterCompositor::InsertCALayerForIOSurface(FlutterView* view,
+                                                  const IOSurfaceRef& io_surface,
                                                   CATransform3D transform) {
-  // Always gets the first view, #0. After Flutter supports multi-view, it
-  // should get the view ID from somewhere.
-  FlutterView* view = GetView(0);
-  if (!view) {
-    return;
-  }
   // FlutterCompositor manages the lifecycle of CALayers.
   CALayer* content_layer = [[CALayer alloc] init];
   content_layer.transform = transform;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index 34b60da002a5a..a1cd6e63decbb 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -80,6 +80,13 @@
 }
 
 bool FlutterMetalCompositor::Present(const FlutterLayer** layers, size_t layers_count) {
+  // Always gets the first view, #0. After Flutter supports multi-view, it
+  // should get the view ID from somewhere.
+  FlutterView* view = GetView(0);
+  if (!view) {
+    return false;
+  }
+
   SetFrameStatus(FrameStatus::kPresenting);
 
   bool has_flutter_content = false;
@@ -93,18 +100,12 @@
           FlutterIOSurfaceHolder* io_surface_holder =
               (__bridge FlutterIOSurfaceHolder*)backing_store->metal.texture.user_data;
           IOSurfaceRef io_surface = [io_surface_holder ioSurface];
-          InsertCALayerForIOSurface(io_surface);
+          InsertCALayerForIOSurface(view, io_surface);
         }
         has_flutter_content = true;
         break;
       }
       case kFlutterLayerContentTypePlatformView: {
-        // Always gets the first view, #0. After Flutter supports multi-view, it
-        // should get the view ID from somewhere.
-        FlutterView* view = GetView(0);
-        if (!view) {
-          return false;
-        }
         PresentPlatformView(view, layer, i);
         break;
       }

From 3bed3d19a0256a2c1b91a450f67e15ee9b4edb73 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 23 Sep 2022 18:20:52 -0700
Subject: [PATCH 04/10] Fix compile

---
 .../darwin/macos/framework/Source/FlutterGLCompositor.mm | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index 6969118d6aa80..de8b76a387cd4 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -77,6 +77,13 @@
 }
 
 bool FlutterGLCompositor::Present(const FlutterLayer** layers, size_t layers_count) {
+  // Always gets the first view, #0. After Flutter supports multi-view, it
+  // should get the view ID from somewhere.
+  FlutterView* view = GetView(0);
+  if (!view) {
+    return false;
+  }
+
   SetFrameStatus(FrameStatus::kPresenting);
 
   bool has_flutter_content = false;
@@ -95,7 +102,7 @@
 
           // The surface is an OpenGL texture, which means it has origin in bottom left corner
           // and needs to be flipped vertically
-          InsertCALayerForIOSurface(io_surface, CATransform3DMakeScale(1, -1, 1));
+          InsertCALayerForIOSurface(view, io_surface, CATransform3DMakeScale(1, -1, 1));
         }
         has_flutter_content = true;
         break;

From 812e2a216f8a4e9e9b09f7c4f78a12a3eb10fae9 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 27 Sep 2022 20:24:12 -0700
Subject: [PATCH 05/10] Fix comment

---
 .../darwin/macos/framework/Source/FlutterEngine.mm  | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index 339d8f8a2a7ee..0db49428d2107 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -428,22 +428,21 @@ - (FlutterCompositor*)createFlutterCompositor {
   // TODO(richardjcai): Add support for creating a FlutterCompositor
   // with a nil _viewController for headless engines.
   // https://github.com/flutter/flutter/issues/71606
-  FlutterViewController* viewController = _viewController;
-  if (!viewController) {
+  if (!_viewController) {
     return nil;
   }
 
   __weak FlutterEngine* weakSelf = self;
 
-  flutter::FlutterCompositor::GetViewCallback get_view_callback =
-      [&viewController](uint64_t view_id) {
-        return viewController == nullptr ? nullptr : viewController.flutterView;
+  flutter::FlutterCompositor::GetViewCallback getViewCallback =
+      [weakSelf](uint64_t view_id) {
+        return weakSelf.viewController == nullptr ? nullptr : weakSelf.viewController.flutterView;
       };
 
   if ([FlutterRenderingBackend renderUsingMetal]) {
     FlutterMetalRenderer* metalRenderer = reinterpret_cast<FlutterMetalRenderer*>(_renderer);
     _macOSCompositor = std::make_unique<flutter::FlutterMetalCompositor>(
-        std::move(get_view_callback), _platformViewController, metalRenderer.device);
+        std::move(getViewCallback), _platformViewController, metalRenderer.device);
     _macOSCompositor->SetPresentCallback([weakSelf](bool has_flutter_content) {
       FlutterMetalRenderer* metalRenderer =
           reinterpret_cast<FlutterMetalRenderer*>(weakSelf.renderer);
@@ -457,7 +456,7 @@ - (FlutterCompositor*)createFlutterCompositor {
   } else {
     FlutterOpenGLRenderer* openGLRenderer = reinterpret_cast<FlutterOpenGLRenderer*>(_renderer);
     [openGLRenderer.openGLContext makeCurrentContext];
-    _macOSCompositor = std::make_unique<flutter::FlutterGLCompositor>(std::move(get_view_callback),
+    _macOSCompositor = std::make_unique<flutter::FlutterGLCompositor>(std::move(getViewCallback),
                                                                       openGLRenderer.openGLContext);
 
     _macOSCompositor->SetPresentCallback([weakSelf](bool has_flutter_content) {

From 118fcdd03ab7640261d4d2ee9057db638579e342 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Tue, 27 Sep 2022 20:25:18 -0700
Subject: [PATCH 06/10] code ctyle

---
 .../darwin/macos/framework/Source/FlutterEngine.mm         | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index 0db49428d2107..290cdcfcd15d7 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -434,10 +434,9 @@ - (FlutterCompositor*)createFlutterCompositor {
 
   __weak FlutterEngine* weakSelf = self;
 
-  flutter::FlutterCompositor::GetViewCallback getViewCallback =
-      [weakSelf](uint64_t view_id) {
-        return weakSelf.viewController == nullptr ? nullptr : weakSelf.viewController.flutterView;
-      };
+  flutter::FlutterCompositor::GetViewCallback getViewCallback = [weakSelf](uint64_t view_id) {
+    return weakSelf.viewController == nullptr ? nullptr : weakSelf.viewController.flutterView;
+  };
 
   if ([FlutterRenderingBackend renderUsingMetal]) {
     FlutterMetalRenderer* metalRenderer = reinterpret_cast<FlutterMetalRenderer*>(_renderer);

From aaebfc32c800bad7a1eaeb1950e535b18c7db335 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 30 Sep 2022 11:01:52 -0700
Subject: [PATCH 07/10] ViewProvider

---
 .../darwin/macos/framework/Source/FlutterCompositor.h       | 6 +++---
 .../darwin/macos/framework/Source/FlutterCompositor.mm      | 2 +-
 .../platform/darwin/macos/framework/Source/FlutterEngine.mm | 2 +-
 .../darwin/macos/framework/Source/FlutterGLCompositor.h     | 2 +-
 .../darwin/macos/framework/Source/FlutterGLCompositor.mm    | 2 +-
 .../macos/framework/Source/FlutterGLCompositorUnittests.mm  | 2 +-
 .../darwin/macos/framework/Source/FlutterMetalCompositor.h  | 2 +-
 .../darwin/macos/framework/Source/FlutterMetalCompositor.mm | 2 +-
 .../framework/Source/FlutterMetalCompositorUnittests.mm     | 2 +-
 9 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
index 6999be7e54b73..07792fbddb26b 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
@@ -19,9 +19,9 @@ namespace flutter {
 // Platform views are not yet supported.
 class FlutterCompositor {
  public:
-  using GetViewCallback = std::function<FlutterView*(uint64_t view_id)>;
+  using ViewProvider = std::function<FlutterView*(uint64_t view_id)>;
 
-  explicit FlutterCompositor(GetViewCallback get_view_callback);
+  explicit FlutterCompositor(ViewProvider get_view_callback);
 
   virtual ~FlutterCompositor() = default;
 
@@ -88,7 +88,7 @@ class FlutterCompositor {
   // A list of the active CALayer objects for the frame that need to be removed.
   std::list<CALayer*> active_ca_layers_;
 
-  GetViewCallback get_view_callback_;
+  ViewProvider get_view_callback_;
 
   // Callback set by the embedder to be called when the layer tree has been
   // correctly set up for this frame.
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
index cf3fcc478268c..3c0490f1fcaa7 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
@@ -7,7 +7,7 @@
 
 namespace flutter {
 
-FlutterCompositor::FlutterCompositor(GetViewCallback get_view_callback) {
+FlutterCompositor::FlutterCompositor(ViewProvider get_view_callback) {
   get_view_callback_ = std::move(get_view_callback);
 }
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index 290cdcfcd15d7..52598b81ced11 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -434,7 +434,7 @@ - (FlutterCompositor*)createFlutterCompositor {
 
   __weak FlutterEngine* weakSelf = self;
 
-  flutter::FlutterCompositor::GetViewCallback getViewCallback = [weakSelf](uint64_t view_id) {
+  flutter::FlutterCompositor::ViewProvider getViewCallback = [weakSelf](uint64_t view_id) {
     return weakSelf.viewController == nullptr ? nullptr : weakSelf.viewController.flutterView;
   };
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
index 24abfc2eda3fc..4ed49110a635a 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
@@ -19,7 +19,7 @@ namespace flutter {
 // FlutterGLCompositor is created and destroyed by FlutterEngine.
 class FlutterGLCompositor : public FlutterCompositor {
  public:
-  FlutterGLCompositor(GetViewCallback get_view_callback,
+  FlutterGLCompositor(ViewProvider get_view_callback,
                       NSOpenGLContext* opengl_context);
 
   virtual ~FlutterGLCompositor() = default;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index de8b76a387cd4..f6113b9ad0c1b 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -19,7 +19,7 @@
 
 namespace flutter {
 
-FlutterGLCompositor::FlutterGLCompositor(GetViewCallback get_view_callback,
+FlutterGLCompositor::FlutterGLCompositor(ViewProvider get_view_callback,
                                          NSOpenGLContext* opengl_context)
     : FlutterCompositor(get_view_callback), open_gl_context_(opengl_context) {}
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
index 2a9da0e49072a..b4693ce136966 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
@@ -13,7 +13,7 @@
 
 TEST(FlutterGLCompositorTest, TestPresent) {
   id mock_view = OCMClassMock([FlutterView class]);
-  flutter::FlutterCompositor::GetViewCallback get_view_callback = [&mock_view](uint64_t view_id) {
+  flutter::FlutterCompositor::ViewProvider get_view_callback = [&mock_view](uint64_t view_id) {
     return mock_view;
   };
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
index 1c142673a6e1e..1cbd21d2a437c 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
@@ -14,7 +14,7 @@ namespace flutter {
 class FlutterMetalCompositor : public FlutterCompositor {
  public:
   explicit FlutterMetalCompositor(
-      GetViewCallback get_view_callback,
+      ViewProvider get_view_callback,
       FlutterPlatformViewController* platform_views_controller,
       id<MTLDevice> mtl_device);
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index a1cd6e63decbb..901f8464071fb 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -11,7 +11,7 @@
 namespace flutter {
 
 FlutterMetalCompositor::FlutterMetalCompositor(
-    GetViewCallback get_view_callback,
+    ViewProvider get_view_callback,
     FlutterPlatformViewController* platform_views_controller,
     id<MTLDevice> mtl_device)
     : FlutterCompositor(get_view_callback),
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
index 531c85fc1a047..a5c4170b1a7b0 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
@@ -11,7 +11,7 @@
 
 namespace flutter::testing {
 
-flutter::FlutterCompositor::GetViewCallback MockGetViewCallback() {
+flutter::FlutterCompositor::ViewProvider MockGetViewCallback() {
   FlutterView* viewMock = OCMClassMock([FlutterView class]);
   FlutterMetalRenderBackingStore* backingStoreMock =
       OCMClassMock([FlutterMetalRenderBackingStore class]);

From 6155d8118a1952b1188e44667812718b3c6e7831 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Fri, 23 Sep 2022 19:18:55 -0700
Subject: [PATCH 08/10] Impl

Format

view -> surface
---
 flow/embedded_views.cc                        |  1 +
 flow/embedded_views.h                         |  1 +
 shell/common/rasterizer.cc                    |  5 +++-
 shell/common/rasterizer_unittests.cc          |  3 ++-
 .../shell_test_external_view_embedder.cc      |  1 +
 .../shell_test_external_view_embedder.h       |  1 +
 .../external_view_embedder.cc                 |  1 +
 .../external_view_embedder.h                  |  1 +
 .../external_view_embedder_unittests.cc       | 16 ++++++-------
 .../framework/Source/FlutterCompositor.h      |  6 +++--
 .../framework/Source/FlutterCompositor.mm     |  4 ++--
 .../macos/framework/Source/FlutterEngine.mm   | 12 ++++++----
 .../framework/Source/FlutterGLCompositor.h    |  4 +++-
 .../framework/Source/FlutterGLCompositor.mm   |  8 +++----
 .../Source/FlutterGLCompositorUnittests.mm    |  2 +-
 .../framework/Source/FlutterMetalCompositor.h |  4 +++-
 .../Source/FlutterMetalCompositor.mm          | 12 ++++------
 .../Source/FlutterMetalCompositorUnittests.mm |  2 +-
 shell/platform/embedder/embedder.cc           | 10 ++++----
 shell/platform/embedder/embedder.h            | 16 +++++++++----
 .../embedder_external_view_embedder.cc        |  9 +++++---
 .../embedder_external_view_embedder.h         |  4 +++-
 shell/platform/embedder/embedder_layers.cc    |  6 ++---
 shell/platform/embedder/embedder_layers.h     |  6 +++--
 .../embedder/tests/embedder_config_builder.cc | 23 +++++++++++--------
 .../tests/embedder_test_compositor.cc         |  3 ++-
 .../embedder/tests/embedder_test_compositor.h |  4 +++-
 .../embedder/tests/embedder_unittests_gl.cc   |  2 +-
 28 files changed, 102 insertions(+), 65 deletions(-)

diff --git a/flow/embedded_views.cc b/flow/embedded_views.cc
index ebc1812755488..caa75b4e7914d 100644
--- a/flow/embedded_views.cc
+++ b/flow/embedded_views.cc
@@ -70,6 +70,7 @@ void DisplayListEmbedderViewSlice::render_into(DisplayListBuilder* builder) {
 }
 
 void ExternalViewEmbedder::SubmitFrame(GrDirectContext* context,
+                                       uint64_t frame_view_id,
                                        std::unique_ptr<SurfaceFrame> frame) {
   frame->Submit();
 };
diff --git a/flow/embedded_views.h b/flow/embedded_views.h
index 14ca2ba12b348..54ef3a5264093 100644
--- a/flow/embedded_views.h
+++ b/flow/embedded_views.h
@@ -405,6 +405,7 @@ class ExternalViewEmbedder {
   //
   // It can also allocate frames for overlay surfaces to compose hybrid views.
   virtual void SubmitFrame(GrDirectContext* context,
+                           uint64_t frame_view_id,
                            std::unique_ptr<SurfaceFrame> frame);
 
   // This method provides the embedder a way to do additional tasks after
diff --git a/shell/common/rasterizer.cc b/shell/common/rasterizer.cc
index 7f66f93ff8830..cf28ac634b29a 100644
--- a/shell/common/rasterizer.cc
+++ b/shell/common/rasterizer.cc
@@ -488,6 +488,9 @@ RasterStatus Rasterizer::DrawToSurface(
 RasterStatus Rasterizer::DrawToSurfaceUnsafe(
     FrameTimingsRecorder& frame_timings_recorder,
     flutter::LayerTree& layer_tree) {
+  // Always gets the first surface, #0. After Flutter supports multi-view, it
+  // should get the surface ID from layer_tree.
+  uint64_t surface_id = 0;
   FML_DCHECK(surface_);
 
   compositor_context_->ui_time().SetLapTime(
@@ -594,7 +597,7 @@ RasterStatus Rasterizer::DrawToSurfaceUnsafe(
     if (external_view_embedder_ &&
         (!raster_thread_merger_ || raster_thread_merger_->IsMerged())) {
       FML_DCHECK(!frame->IsSubmitted());
-      external_view_embedder_->SubmitFrame(surface_->GetContext(),
+      external_view_embedder_->SubmitFrame(surface_->GetContext(), surface_id,
                                            std::move(frame));
     } else {
       frame->Submit();
diff --git a/shell/common/rasterizer_unittests.cc b/shell/common/rasterizer_unittests.cc
index a6f7ab7159e5d..1daa29a2cfe9f 100644
--- a/shell/common/rasterizer_unittests.cc
+++ b/shell/common/rasterizer_unittests.cc
@@ -69,8 +69,9 @@ class MockExternalViewEmbedder : public ExternalViewEmbedder {
   MOCK_METHOD0(GetCurrentCanvases, std::vector<SkCanvas*>());
   MOCK_METHOD0(GetCurrentBuilders, std::vector<DisplayListBuilder*>());
   MOCK_METHOD1(CompositeEmbeddedView, EmbedderPaintContext(int view_id));
-  MOCK_METHOD2(SubmitFrame,
+  MOCK_METHOD3(SubmitFrame,
                void(GrDirectContext* context,
+                    uint64_t frame_view_id,
                     std::unique_ptr<SurfaceFrame> frame));
   MOCK_METHOD2(EndFrame,
                void(bool should_resubmit_frame,
diff --git a/shell/common/shell_test_external_view_embedder.cc b/shell/common/shell_test_external_view_embedder.cc
index 789ebc22d72b8..9051a78e5aa50 100644
--- a/shell/common/shell_test_external_view_embedder.cc
+++ b/shell/common/shell_test_external_view_embedder.cc
@@ -106,6 +106,7 @@ EmbedderPaintContext ShellTestExternalViewEmbedder::CompositeEmbeddedView(
 // |ExternalViewEmbedder|
 void ShellTestExternalViewEmbedder::SubmitFrame(
     GrDirectContext* context,
+    uint64_t frame_view_id,
     std::unique_ptr<SurfaceFrame> frame) {
   if (!frame) {
     return;
diff --git a/shell/common/shell_test_external_view_embedder.h b/shell/common/shell_test_external_view_embedder.h
index 583a09182e5fc..17b847422d460 100644
--- a/shell/common/shell_test_external_view_embedder.h
+++ b/shell/common/shell_test_external_view_embedder.h
@@ -80,6 +80,7 @@ class ShellTestExternalViewEmbedder final : public ExternalViewEmbedder {
 
   // |ExternalViewEmbedder|
   void SubmitFrame(GrDirectContext* context,
+                   uint64_t frame_view_id,
                    std::unique_ptr<SurfaceFrame> frame) override;
 
   // |ExternalViewEmbedder|
diff --git a/shell/platform/android/external_view_embedder/external_view_embedder.cc b/shell/platform/android/external_view_embedder/external_view_embedder.cc
index c1054c78b9ee6..be7d6c6f05ed3 100644
--- a/shell/platform/android/external_view_embedder/external_view_embedder.cc
+++ b/shell/platform/android/external_view_embedder/external_view_embedder.cc
@@ -99,6 +99,7 @@ SkRect AndroidExternalViewEmbedder::GetViewRect(int view_id) const {
 // |ExternalViewEmbedder|
 void AndroidExternalViewEmbedder::SubmitFrame(
     GrDirectContext* context,
+    uint64_t frame_view_id,
     std::unique_ptr<SurfaceFrame> frame) {
   TRACE_EVENT0("flutter", "AndroidExternalViewEmbedder::SubmitFrame");
 
diff --git a/shell/platform/android/external_view_embedder/external_view_embedder.h b/shell/platform/android/external_view_embedder/external_view_embedder.h
index 0b258854408d6..d3655b98091ba 100644
--- a/shell/platform/android/external_view_embedder/external_view_embedder.h
+++ b/shell/platform/android/external_view_embedder/external_view_embedder.h
@@ -55,6 +55,7 @@ class AndroidExternalViewEmbedder final : public ExternalViewEmbedder {
 
   // |ExternalViewEmbedder|
   void SubmitFrame(GrDirectContext* context,
+                   uint64_t frame_view_id,
                    std::unique_ptr<SurfaceFrame> frame) override;
 
   // |ExternalViewEmbedder|
diff --git a/shell/platform/android/external_view_embedder/external_view_embedder_unittests.cc b/shell/platform/android/external_view_embedder/external_view_embedder_unittests.cc
index b174cd92703f9..c71425451ee74 100644
--- a/shell/platform/android/external_view_embedder/external_view_embedder_unittests.cc
+++ b/shell/platform/android/external_view_embedder/external_view_embedder_unittests.cc
@@ -371,7 +371,7 @@ TEST(AndroidExternalViewEmbedder, SubmitFrame) {
         },
         /*frame_size=*/SkISize::Make(800, 600));
 
-    embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+    embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
     // Submits frame if no Android view in the current frame.
     EXPECT_TRUE(did_submit_frame);
     // Doesn't resubmit frame.
@@ -439,7 +439,7 @@ TEST(AndroidExternalViewEmbedder, SubmitFrame) {
         },
         /*frame_size=*/SkISize::Make(800, 600));
 
-    embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+    embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
     // Doesn't submit frame if there aren't Android views in the previous frame.
     EXPECT_FALSE(did_submit_frame);
     // Resubmits frame.
@@ -504,7 +504,7 @@ TEST(AndroidExternalViewEmbedder, SubmitFrame) {
           return true;
         },
         /*frame_size=*/SkISize::Make(800, 600));
-    embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+    embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
     // Submits frame if there are Android views in the previous frame.
     EXPECT_TRUE(did_submit_frame);
     // Doesn't resubmit frame.
@@ -614,7 +614,7 @@ TEST(AndroidExternalViewEmbedder, SubmitFrameOverlayComposition) {
       },
       /*frame_size=*/SkISize::Make(800, 600));
 
-  embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+  embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
 
   EXPECT_CALL(*jni_mock, FlutterViewEndFrame());
   embedder->EndFrame(/*should_resubmit_frame=*/false, raster_thread_merger);
@@ -683,7 +683,7 @@ TEST(AndroidExternalViewEmbedder, SubmitFramePlatformViewWithoutAnyOverlay) {
       },
       /*frame_size=*/SkISize::Make(800, 600));
 
-  embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+  embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
 
   EXPECT_CALL(*jni_mock, FlutterViewEndFrame());
   embedder->EndFrame(/*should_resubmit_frame=*/false, raster_thread_merger);
@@ -785,7 +785,7 @@ TEST(AndroidExternalViewEmbedder, DestroyOverlayLayersOnSizeChange) {
           return true;
         },
         /*frame_size=*/SkISize::Make(800, 600));
-    embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+    embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
 
     EXPECT_CALL(*jni_mock, FlutterViewEndFrame());
     embedder->EndFrame(/*should_resubmit_frame=*/false, raster_thread_merger);
@@ -873,7 +873,7 @@ TEST(AndroidExternalViewEmbedder, DoesNotDestroyOverlayLayersOnSizeChange) {
           return true;
         },
         /*frame_size=*/SkISize::Make(800, 600));
-    embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+    embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
 
     EXPECT_CALL(*jni_mock, FlutterViewEndFrame());
     embedder->EndFrame(/*should_resubmit_frame=*/false, raster_thread_merger);
@@ -985,7 +985,7 @@ TEST(AndroidExternalViewEmbedder, Teardown) {
       SkSurface::MakeNull(1000, 1000), framebuffer_info,
       [](const SurfaceFrame& surface_frame, SkCanvas* canvas) { return true; },
       /*frame_size=*/SkISize::Make(800, 600));
-  embedder->SubmitFrame(gr_context.get(), std::move(surface_frame));
+  embedder->SubmitFrame(gr_context.get(), 0, std::move(surface_frame));
 
   embedder->EndFrame(/*should_resubmit_frame=*/false, raster_thread_merger);
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
index 07792fbddb26b..6758aaf3e07ee 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h
@@ -46,7 +46,9 @@ class FlutterCompositor {
   // Presents the FlutterLayers by updating FlutterView(s) using the
   // layer content.
   // Present sets frame_started_ to false.
-  virtual bool Present(const FlutterLayer** layers, size_t layers_count) = 0;
+  virtual bool Present(uint64_t surface_id,
+                       const FlutterLayer** layers,
+                       size_t layers_count) = 0;
 
   using PresentCallback = std::function<bool(bool has_flutter_content)>;
 
@@ -64,7 +66,7 @@ class FlutterCompositor {
   typedef enum { kStarted, kPresenting, kEnded } FrameStatus;
 
  protected:
-  FlutterView* GetView(uint64_t view_id);
+  FlutterView* GetView(uint64_t surface_id);
 
   // Gets and sets the FrameStatus for the current frame.
   void SetFrameStatus(FrameStatus frame_status);
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
index 3c0490f1fcaa7..fe15d798dc62e 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterCompositor.mm
@@ -33,8 +33,8 @@
   return status;
 }
 
-FlutterView* FlutterCompositor::GetView(uint64_t view_id) {
-  return get_view_callback_(view_id);
+FlutterView* FlutterCompositor::GetView(uint64_t surface_id) {
+  return get_view_callback_(surface_id);
 }
 
 void FlutterCompositor::SetFrameStatus(FlutterCompositor::FrameStatus frame_status) {
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index 8931ab1432d19..820fa59b5b910 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -476,11 +476,13 @@ - (FlutterCompositor*)createFlutterCompositor {
         backing_store);
   };
 
-  _compositor.present_layers_callback = [](const FlutterLayer** layers,  //
-                                           size_t layers_count,          //
-                                           void* user_data               //
-                                        ) {
-    return reinterpret_cast<flutter::FlutterCompositor*>(user_data)->Present(layers, layers_count);
+  _compositor.present_layers_surface_callback = [](uint64_t surface_id,          //
+                                                   const FlutterLayer** layers,  //
+                                                   size_t layers_count,          //
+                                                   void* user_data               //
+                                                ) {
+    return reinterpret_cast<flutter::FlutterCompositor*>(user_data)->Present(surface_id, layers,
+                                                                             layers_count);
   };
 
   _compositor.avoid_backing_store_cache = true;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
index 4ed49110a635a..64f816b2e8d2d 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h
@@ -44,7 +44,9 @@ class FlutterGLCompositor : public FlutterCompositor {
   // Presents the FlutterLayers by updating FlutterView(s) using the
   // layer content.
   // Present sets frame_started_ to false.
-  bool Present(const FlutterLayer** layers, size_t layers_count) override;
+  bool Present(uint64_t surface_id,
+               const FlutterLayer** layers,
+               size_t layers_count) override;
 
  private:
   const NSOpenGLContext* open_gl_context_;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index f6113b9ad0c1b..b718bb34b42e0 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -25,9 +25,7 @@
 
 bool FlutterGLCompositor::CreateBackingStore(const FlutterBackingStoreConfig* config,
                                              FlutterBackingStore* backing_store_out) {
-  // Always gets the first view, #0. After Flutter supports multi-view, it
-  // should get the view ID from somewhere.
-  FlutterView* view = GetView(0);
+  FlutterView* view = GetView(config->surface_id);
   if (!view) {
     return false;
   }
@@ -76,7 +74,9 @@
   return true;
 }
 
-bool FlutterGLCompositor::Present(const FlutterLayer** layers, size_t layers_count) {
+bool FlutterGLCompositor::Present(uint64_t surface_id,
+                                  const FlutterLayer** layers,
+                                  size_t layers_count) {
   // Always gets the first view, #0. After Flutter supports multi-view, it
   // should get the view ID from somewhere.
   FlutterView* view = GetView(0);
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
index b4693ce136966..9d5031828a09d 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm
@@ -26,7 +26,7 @@
     return true;
   });
 
-  ASSERT_TRUE(macos_compositor->Present(nil, 0));
+  ASSERT_TRUE(macos_compositor->Present(0, nil, 0));
   ASSERT_TRUE(flag);
 }
 
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
index 1cbd21d2a437c..d5181cce1daab 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.h
@@ -42,7 +42,9 @@ class FlutterMetalCompositor : public FlutterCompositor {
 
   // Composites the provided FlutterLayer objects and presents the composited
   // frame to the FlutterView(s).
-  bool Present(const FlutterLayer** layers, size_t layers_count) override;
+  bool Present(uint64_t surface_id,
+               const FlutterLayer** layers,
+               size_t layers_count) override;
 
  private:
   // Presents the platform view layer represented by `layer`. `layer_index` is
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index 901f8464071fb..edc57ac367f83 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -20,9 +20,7 @@
 
 bool FlutterMetalCompositor::CreateBackingStore(const FlutterBackingStoreConfig* config,
                                                 FlutterBackingStore* backing_store_out) {
-  // Always gets the first view, #0. After Flutter supports multi-view, it
-  // should get the view ID from somewhere.
-  FlutterView* view = GetView(0);
+  FlutterView* view = GetView(config->surface_id);
   if (!view) {
     return false;
   }
@@ -79,10 +77,10 @@
   return true;
 }
 
-bool FlutterMetalCompositor::Present(const FlutterLayer** layers, size_t layers_count) {
-  // Always gets the first view, #0. After Flutter supports multi-view, it
-  // should get the view ID from somewhere.
-  FlutterView* view = GetView(0);
+bool FlutterMetalCompositor::Present(uint64_t surface_id,
+                                     const FlutterLayer** layers,
+                                     size_t layers_count) {
+  FlutterView* view = GetView(surface_id);
   if (!view) {
     return false;
   }
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
index a5c4170b1a7b0..2a63b38335ade 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm
@@ -41,7 +41,7 @@
     return true;
   });
 
-  ASSERT_TRUE(macos_compositor->Present(nil, 0));
+  ASSERT_TRUE(macos_compositor->Present(0, nil, 0));
   ASSERT_TRUE(flag);
 }
 
diff --git a/shell/platform/embedder/embedder.cc b/shell/platform/embedder/embedder.cc
index dcb19c02028ff..d090343ee8479 100644
--- a/shell/platform/embedder/embedder.cc
+++ b/shell/platform/embedder/embedder.cc
@@ -1034,7 +1034,7 @@ InferExternalViewEmbedderFromArgs(const FlutterCompositor* compositor) {
   auto c_collect_callback =
       SAFE_ACCESS(compositor, collect_backing_store_callback, nullptr);
   auto c_present_callback =
-      SAFE_ACCESS(compositor, present_layers_callback, nullptr);
+      SAFE_ACCESS(compositor, present_layers_surface_callback, nullptr);
   bool avoid_backing_store_cache =
       SAFE_ACCESS(compositor, avoid_backing_store_cache, false);
 
@@ -1054,12 +1054,12 @@ InferExternalViewEmbedderFromArgs(const FlutterCompositor* compositor) {
           };
 
   flutter::EmbedderExternalViewEmbedder::PresentCallback present_callback =
-      [c_present_callback,
-       user_data = compositor->user_data](const auto& layers) {
+      [c_present_callback, user_data = compositor->user_data](
+          uint64_t surface_id, const auto& layers) {
         TRACE_EVENT0("flutter", "FlutterCompositorPresentLayers");
         return c_present_callback(
-            const_cast<const FlutterLayer**>(layers.data()), layers.size(),
-            user_data);
+            surface_id, const_cast<const FlutterLayer**>(layers.data()),
+            layers.size(), user_data);
       };
 
   return {std::make_unique<flutter::EmbedderExternalViewEmbedder>(
diff --git a/shell/platform/embedder/embedder.h b/shell/platform/embedder/embedder.h
index c12452c788490..72a66d2385f89 100644
--- a/shell/platform/embedder/embedder.h
+++ b/shell/platform/embedder/embedder.h
@@ -1371,6 +1371,8 @@ typedef struct {
   size_t struct_size;
   /// The size of the render target the engine expects to render into.
   FlutterSize size;
+  /// Indicates the view that owns the layer this store is backing.
+  uint64_t surface_id;
 } FlutterBackingStoreConfig;
 
 typedef enum {
@@ -1414,6 +1416,10 @@ typedef bool (*FlutterBackingStoreCollectCallback)(
 typedef bool (*FlutterLayersPresentCallback)(const FlutterLayer** layers,
                                              size_t layers_count,
                                              void* user_data);
+typedef bool (*FlutterLayersPresentSurfaceCallback)(uint64_t surface_id,
+                                                    const FlutterLayer** layers,
+                                                    size_t layers_count,
+                                                    void* user_data);
 
 typedef struct {
   /// This size of this struct. Must be sizeof(FlutterCompositor).
@@ -1421,7 +1427,7 @@ typedef struct {
   /// A baton that in not interpreted by the engine in any way. If it passed
   /// back to the embedder in `FlutterCompositor.create_backing_store_callback`,
   /// `FlutterCompositor.collect_backing_store_callback` and
-  /// `FlutterCompositor.present_layers_callback`
+  /// `FlutterCompositor.present_layers_surface_callback`
   void* user_data;
   /// A callback invoked by the engine to obtain a backing store for a specific
   /// `FlutterLayer`.
@@ -1434,11 +1440,13 @@ typedef struct {
   /// A callback invoked by the engine to release the backing store. The
   /// embedder may collect any resources associated with the backing store.
   FlutterBackingStoreCollectCallback collect_backing_store_callback;
-  /// Callback invoked by the engine to composite the contents of each layer
-  /// onto the screen.
-  FlutterLayersPresentCallback present_layers_callback;
+  /// A deprecated callback. It is not used and should not be set.
+  void* _deprecated_present_layers_callback;
   /// Avoid caching backing stores provided by this compositor.
   bool avoid_backing_store_cache;
+  /// Callback invoked by the engine to composite the contents of each layer
+  /// onto the screen.
+  FlutterLayersPresentSurfaceCallback present_layers_surface_callback;
 } FlutterCompositor;
 
 typedef struct {
diff --git a/shell/platform/embedder/embedder_external_view_embedder.cc b/shell/platform/embedder/embedder_external_view_embedder.cc
index 0e61db48ce8d8..0371abdd09f68 100644
--- a/shell/platform/embedder/embedder_external_view_embedder.cc
+++ b/shell/platform/embedder/embedder_external_view_embedder.cc
@@ -131,13 +131,15 @@ EmbedderPaintContext EmbedderExternalViewEmbedder::CompositeEmbeddedView(
 }
 
 static FlutterBackingStoreConfig MakeBackingStoreConfig(
-    const SkISize& backing_store_size) {
+    const SkISize& backing_store_size,
+    uint64_t surface_id) {
   FlutterBackingStoreConfig config = {};
 
   config.struct_size = sizeof(config);
 
   config.size.width = backing_store_size.width();
   config.size.height = backing_store_size.height();
+  config.surface_id = surface_id;
 
   return config;
 }
@@ -145,6 +147,7 @@ static FlutterBackingStoreConfig MakeBackingStoreConfig(
 // |ExternalViewEmbedder|
 void EmbedderExternalViewEmbedder::SubmitFrame(
     GrDirectContext* context,
+    uint64_t frame_view_id,
     std::unique_ptr<SurfaceFrame> frame) {
   auto [matched_render_targets, pending_keys] =
       render_target_cache_.GetExistingTargetsInCache(pending_views_);
@@ -184,7 +187,7 @@ void EmbedderExternalViewEmbedder::SubmitFrame(
     const auto render_surface_size = external_view->GetRenderSurfaceSize();
 
     const auto backing_store_config =
-        MakeBackingStoreConfig(render_surface_size);
+        MakeBackingStoreConfig(render_surface_size, frame_view_id);
 
     // This is where the embedder will create render targets for us. Control
     // flow to the embedder makes the engine susceptible to having the embedder
@@ -263,7 +266,7 @@ void EmbedderExternalViewEmbedder::SubmitFrame(
     // Flush the layer description down to the embedder for presentation.
     //
     // @warning: Embedder may trample on our OpenGL context here.
-    presented_layers.InvokePresentCallback(present_callback_);
+    presented_layers.InvokePresentCallback(present_callback_, frame_view_id);
   }
 
   // See why this is necessary in the comment where this collection in realized.
diff --git a/shell/platform/embedder/embedder_external_view_embedder.h b/shell/platform/embedder/embedder_external_view_embedder.h
index 7921cb8b78255..8edad877dd2c7 100644
--- a/shell/platform/embedder/embedder_external_view_embedder.h
+++ b/shell/platform/embedder/embedder_external_view_embedder.h
@@ -33,7 +33,8 @@ class EmbedderExternalViewEmbedder final : public ExternalViewEmbedder {
           GrDirectContext* context,
           const FlutterBackingStoreConfig& config)>;
   using PresentCallback =
-      std::function<bool(const std::vector<const FlutterLayer*>& layers)>;
+      std::function<bool(uint64_t surface_id,
+                         const std::vector<const FlutterLayer*>& layers)>;
   using SurfaceTransformationCallback = std::function<SkMatrix(void)>;
 
   //----------------------------------------------------------------------------
@@ -101,6 +102,7 @@ class EmbedderExternalViewEmbedder final : public ExternalViewEmbedder {
 
   // |ExternalViewEmbedder|
   void SubmitFrame(GrDirectContext* context,
+                   uint64_t frame_view_id,
                    std::unique_ptr<SurfaceFrame> frame) override;
 
   // |ExternalViewEmbedder|
diff --git a/shell/platform/embedder/embedder_layers.cc b/shell/platform/embedder/embedder_layers.cc
index 6465293748f9f..e612779dd73b9 100644
--- a/shell/platform/embedder/embedder_layers.cc
+++ b/shell/platform/embedder/embedder_layers.cc
@@ -199,14 +199,14 @@ void EmbedderLayers::PushPlatformViewLayer(
   presented_layers_.push_back(layer);
 }
 
-void EmbedderLayers::InvokePresentCallback(
-    const PresentCallback& callback) const {
+void EmbedderLayers::InvokePresentCallback(const PresentCallback& callback,
+                                           uint64_t frame_view_id) const {
   std::vector<const FlutterLayer*> presented_layers_pointers;
   presented_layers_pointers.reserve(presented_layers_.size());
   for (const auto& layer : presented_layers_) {
     presented_layers_pointers.push_back(&layer);
   }
-  callback(presented_layers_pointers);
+  callback(frame_view_id, presented_layers_pointers);
 }
 
 }  // namespace flutter
diff --git a/shell/platform/embedder/embedder_layers.h b/shell/platform/embedder/embedder_layers.h
index c1cb2907588c9..9ad7bb64c3b70 100644
--- a/shell/platform/embedder/embedder_layers.h
+++ b/shell/platform/embedder/embedder_layers.h
@@ -30,8 +30,10 @@ class EmbedderLayers {
                              const EmbeddedViewParams& params);
 
   using PresentCallback =
-      std::function<bool(const std::vector<const FlutterLayer*>& layers)>;
-  void InvokePresentCallback(const PresentCallback& callback) const;
+      std::function<bool(uint64_t surface_id,
+                         const std::vector<const FlutterLayer*>& layers)>;
+  void InvokePresentCallback(const PresentCallback& callback,
+                             uint64_t frame_view_id) const;
 
  private:
   const SkISize frame_size_;
diff --git a/shell/platform/embedder/tests/embedder_config_builder.cc b/shell/platform/embedder/tests/embedder_config_builder.cc
index 58e48c4b594d8..dfa32fa7bcb44 100644
--- a/shell/platform/embedder/tests/embedder_config_builder.cc
+++ b/shell/platform/embedder/tests/embedder_config_builder.cc
@@ -355,16 +355,19 @@ void EmbedderConfigBuilder::SetCompositor(bool avoid_backing_store_cache) {
         return reinterpret_cast<EmbedderTestCompositor*>(user_data)
             ->CollectBackingStore(backing_store);
       };
-  compositor_.present_layers_callback = [](const FlutterLayer** layers,  //
-                                           size_t layers_count,          //
-                                           void* user_data               //
-                                        ) {
-    return reinterpret_cast<EmbedderTestCompositor*>(user_data)->Present(
-        layers,       //
-        layers_count  //
-
-    );
-  };
+  compositor_.present_layers_surface_callback =
+      [](uint64_t surface_id,
+         const FlutterLayer** layers,  //
+         size_t layers_count,          //
+         void* user_data               //
+      ) {
+        return reinterpret_cast<EmbedderTestCompositor*>(user_data)->Present(
+            surface_id,
+            layers,       //
+            layers_count  //
+
+        );
+      };
   compositor_.avoid_backing_store_cache = avoid_backing_store_cache;
   project_args_.compositor = &compositor_;
 }
diff --git a/shell/platform/embedder/tests/embedder_test_compositor.cc b/shell/platform/embedder/tests/embedder_test_compositor.cc
index 23afb36f01e72..bdd2d4297cbe7 100644
--- a/shell/platform/embedder/tests/embedder_test_compositor.cc
+++ b/shell/platform/embedder/tests/embedder_test_compositor.cc
@@ -58,7 +58,8 @@ sk_sp<SkImage> EmbedderTestCompositor::GetLastComposition() {
   return last_composition_;
 }
 
-bool EmbedderTestCompositor::Present(const FlutterLayer** layers,
+bool EmbedderTestCompositor::Present(uint64_t view_id,
+                                     const FlutterLayer** layers,
                                      size_t layers_count) {
   if (!UpdateOffscrenComposition(layers, layers_count)) {
     FML_LOG(ERROR)
diff --git a/shell/platform/embedder/tests/embedder_test_compositor.h b/shell/platform/embedder/tests/embedder_test_compositor.h
index 26d96de6cda81..79393e0e54759 100644
--- a/shell/platform/embedder/tests/embedder_test_compositor.h
+++ b/shell/platform/embedder/tests/embedder_test_compositor.h
@@ -36,7 +36,9 @@ class EmbedderTestCompositor {
 
   bool CollectBackingStore(const FlutterBackingStore* backing_store);
 
-  bool Present(const FlutterLayer** layers, size_t layers_count);
+  bool Present(uint64_t view_id,
+               const FlutterLayer** layers,
+               size_t layers_count);
 
   void SetPlatformViewRendererCallback(
       const PlatformViewRendererCallback& callback);
diff --git a/shell/platform/embedder/tests/embedder_unittests_gl.cc b/shell/platform/embedder/tests/embedder_unittests_gl.cc
index 08f653495f379..cd2b8840a4946 100644
--- a/shell/platform/embedder/tests/embedder_unittests_gl.cc
+++ b/shell/platform/embedder/tests/embedder_unittests_gl.cc
@@ -71,7 +71,7 @@ TEST_F(EmbedderTest,
   builder.SetCompositor();
   builder.GetCompositor().create_backing_store_callback = nullptr;
   builder.GetCompositor().collect_backing_store_callback = nullptr;
-  builder.GetCompositor().present_layers_callback = nullptr;
+  builder.GetCompositor().present_layers_surface_callback = nullptr;
   auto engine = builder.LaunchEngine();
   ASSERT_FALSE(engine.is_valid());
 }

From 4c7fc3a3838c742faf3a3d64341a23363ba9f156 Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Thu, 3 Nov 2022 13:43:03 -0700
Subject: [PATCH 09/10] Compile

---
 .../darwin/macos/framework/Source/FlutterEngine.mm         | 4 ----
 .../darwin/macos/framework/Source/FlutterGLCompositor.mm   | 7 ++-----
 .../macos/framework/Source/FlutterMetalCompositor.mm       | 7 ++-----
 3 files changed, 4 insertions(+), 14 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
index 241e57c51bc8f..1df8303dc9a11 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterEngine.mm
@@ -438,10 +438,6 @@ - (FlutterCompositor*)createFlutterCompositor {
 
   __weak FlutterEngine* weakSelf = self;
 
-  flutter::FlutterCompositor::ViewProvider getViewCallback = [weakSelf](uint64_t view_id) {
-    return weakSelf.viewController == nullptr ? nullptr : weakSelf.viewController.flutterView;
-  };
-
   if ([FlutterRenderingBackend renderUsingMetal]) {
     FlutterMetalRenderer* metalRenderer = reinterpret_cast<FlutterMetalRenderer*>(_renderer);
     _macOSCompositor = std::make_unique<flutter::FlutterMetalCompositor>(
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index 8ab6a993f8c86..f5454cae7e499 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -77,11 +77,8 @@
   return true;
 }
 
-bool FlutterGLCompositor::Present(const FlutterLayer** layers, size_t layers_count) {
-  // TODO(dkwingsmt): This class only supports single-view for now. As more
-  // classes are gradually converted to multi-view, it should get the view ID
-  // from somewhere.
-  FlutterView* view = GetView(kFlutterDefaultViewId);
+bool FlutterGLCompositor::Present(uint64_t surface_id, const FlutterLayer** layers, size_t layers_count) {
+  FlutterView* view = GetView(surface_id);
   if (!view) {
     return false;
   }
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index 74eae76f8e885..d7932294bee56 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -80,11 +80,8 @@
   return true;
 }
 
-bool FlutterMetalCompositor::Present(const FlutterLayer** layers, size_t layers_count) {
-  // TODO(dkwingsmt): This class only supports single-view for now. As more
-  // classes are gradually converted to multi-view, it should get the view ID
-  // from somewhere.
-  FlutterView* view = GetView(kFlutterDefaultViewId);
+bool FlutterMetalCompositor::Present(uint64_t surface_id, const FlutterLayer** layers, size_t layers_count) {
+  FlutterView* view = GetView(surface_id);
   if (!view) {
     return false;
   }

From ac057c03fd3118aaedfd466cfa902e4ab79d479b Mon Sep 17 00:00:00 2001
From: Tong Mu <dkwingsmt@gmail.com>
Date: Thu, 3 Nov 2022 13:45:34 -0700
Subject: [PATCH 10/10] Format

---
 .../darwin/macos/framework/Source/FlutterGLCompositor.mm      | 4 +++-
 .../darwin/macos/framework/Source/FlutterMetalCompositor.mm   | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
index f5454cae7e499..7400196543fce 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm
@@ -77,7 +77,9 @@
   return true;
 }
 
-bool FlutterGLCompositor::Present(uint64_t surface_id, const FlutterLayer** layers, size_t layers_count) {
+bool FlutterGLCompositor::Present(uint64_t surface_id,
+                                  const FlutterLayer** layers,
+                                  size_t layers_count) {
   FlutterView* view = GetView(surface_id);
   if (!view) {
     return false;
diff --git a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
index d7932294bee56..148341651ae38 100644
--- a/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
+++ b/shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm
@@ -80,7 +80,9 @@
   return true;
 }
 
-bool FlutterMetalCompositor::Present(uint64_t surface_id, const FlutterLayer** layers, size_t layers_count) {
+bool FlutterMetalCompositor::Present(uint64_t surface_id,
+                                     const FlutterLayer** layers,
+                                     size_t layers_count) {
   FlutterView* view = GetView(surface_id);
   if (!view) {
     return false;