sync compositor: Reduce begin frame sync IPC overhead

content/browser/android/synchronous_compositor_host.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_HOST_H_
 #define CONTENT_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_HOST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 14 matching lines @@
 }
 
 namespace blink {
 class WebInputEvent;
 }
 
 namespace cc {
 struct BeginFrameArgs;
 }
 
+namespace ui {
+class WindowAndroid;
+}
+
 namespace content {
 
 class RenderWidgetHostViewAndroid;
 class SynchronousCompositorClient;
+class SynchronousCompositorObserver;
 class WebContents;
 struct DidOverscrollParams;
 struct SyncCompositorCommonRendererParams;
 
 class SynchronousCompositorHost : public SynchronousCompositor {
  public:
   static std::unique_ptr<SynchronousCompositorHost> Create(
       RenderWidgetHostViewAndroid* rwhva,
       WebContents* web_contents);
 
@@ skipping 10 matching lines @@
   bool DemandDrawSw(SkCanvas* canvas) override;
   void ReturnResources(uint32_t output_surface_id,
                        const cc::ReturnedResourceArray& resources) override;
   void SetMemoryPolicy(size_t bytes_limit) override;
   void DidChangeRootLayerScrollOffset(
       const gfx::ScrollOffset& root_offset) override;
   void SynchronouslyZoomBy(float zoom_delta, const gfx::Point& anchor) override;
   void OnComputeScroll(base::TimeTicks animation_time) override;
 
   void DidOverscroll(const DidOverscrollParams& over_scroll_params);
-  void DidSendBeginFrame();
+  void DidSendBeginFrame(ui::WindowAndroid* window_android);
   bool OnMessageReceived(const IPC::Message& message);
 
+  // Called by SynchronousCompositorObserver.
+  int routing_id() const { return routing_id_; }
+  void ProcessCommonParams(const SyncCompositorCommonRendererParams& params);
+
  private:
   class ScopedSendZeroMemory;
   struct SharedMemoryWithSize;
   friend class ScopedSetZeroMemory;
   friend class SynchronousCompositorBase;
 
   SynchronousCompositorHost(RenderWidgetHostViewAndroid* rwhva,
                             SynchronousCompositorClient* client,
                             bool use_in_proc_software_draw);
-  void ProcessCommonParams(const SyncCompositorCommonRendererParams& params);
   void UpdateFrameMetaData(cc::CompositorFrameMetadata frame_metadata);
   void OutputSurfaceCreated();
   bool DemandDrawSwInProc(SkCanvas* canvas);
   void SetSoftwareDrawSharedMemoryIfNeeded(size_t stride, size_t buffer_size);
   void SendZeroMemory();
 
   RenderWidgetHostViewAndroid* const rwhva_;
   SynchronousCompositorClient* const client_;
   const scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner_;
   const int process_id_;
   const int routing_id_;
+  SynchronousCompositorObserver* const rph_observer_;
   IPC::Sender* const sender_;
   const bool use_in_process_zero_copy_software_draw_;
 
   size_t bytes_limit_;
   std::unique_ptr<SharedMemoryWithSize> software_draw_shm_;
 
   // Updated by both renderer and browser.
   gfx::ScrollOffset root_scroll_offset_;
 
   // From renderer.
   uint32_t renderer_param_version_;
   bool need_animate_scroll_;
   uint32_t need_invalidate_count_;
   uint32_t did_activate_pending_tree_count_;
 
   DISALLOW_COPY_AND_ASSIGN(SynchronousCompositorHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_HOST_H_