[Multiwindow] Backing store and compositor

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();
 };

flow/embedded_views.h

@@ -438,6 +438,7 @@ 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

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(
@@ -595,7 +598,7 @@ 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();

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,

shell/common/shell_test_external_view_embedder.cc

@@ -107,6 +107,7 @@ EmbedderPaintContext ShellTestExternalViewEmbedder::CompositeEmbeddedView(
 // |ExternalViewEmbedder|
 void ShellTestExternalViewEmbedder::SubmitFrame(
     GrDirectContext* context,
+    uint64_t frame_view_id,
     std::unique_ptr<SurfaceFrame> frame) {
   if (!frame) {
     return;

shell/common/shell_test_external_view_embedder.h

@@ -81,6 +81,7 @@ class ShellTestExternalViewEmbedder final : public ExternalViewEmbedder {
 
   // |ExternalViewEmbedder|
   void SubmitFrame(GrDirectContext* context,
+                   uint64_t frame_view_id,
                    std::unique_ptr<SurfaceFrame> frame) override;
 
   // |ExternalViewEmbedder|

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");
 

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|

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);
 

shell/platform/darwin/macos/framework/Source/FlutterCompositor.h

@@ -50,7 +50,9 @@ 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)>;
 

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;

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_;

shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm

@@ -77,11 +77,10 @@
   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;
   }

shell/platform/darwin/macos/framework/Source/FlutterGLCompositorUnittests.mm

@@ -56,7 +56,7 @@ - (nullable FlutterView*)getView:(uint64_t)viewId {
     return true;
   });
 
-  ASSERT_TRUE(macos_compositor->Present(nil, 0));
+  ASSERT_TRUE(macos_compositor->Present(0, nil, 0));
   ASSERT_TRUE(flag);
 }
 

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

shell/platform/darwin/macos/framework/Source/FlutterMetalCompositor.mm

@@ -80,11 +80,10 @@
   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;
   }

shell/platform/darwin/macos/framework/Source/FlutterMetalCompositorUnittests.mm

@@ -73,7 +73,7 @@ - (nullable FlutterView*)getView:(uint64_t)viewId {
     return true;
   });
 
-  ASSERT_TRUE(macos_compositor->Present(nil, 0));
+  ASSERT_TRUE(macos_compositor->Present(0, nil, 0));
   ASSERT_TRUE(flag);
 }
 

shell/platform/embedder/embedder.cc

@@ -1038,7 +1038,7 @@ 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);
 
@@ -1058,12 +1058,12 @@ 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>(

shell/platform/embedder/embedder.h

@@ -1381,6 +1381,8 @@ 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 {
@@ -1424,14 +1426,18 @@ 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).
   size_t struct_size;
   /// 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`.
@@ -1444,11 +1450,13 @@ 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 {

shell/platform/embedder/embedder_external_view_embedder.cc

@@ -131,20 +131,23 @@ 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;
 }
 
 // |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.

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|