IPC-based sync compositor software draw optimization

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 38 matching lines @@
   void OnComputeScroll(base::TimeTicks animation_time) override;
 
   // SynchronousCompositorBase overrides.
   InputEventAckState HandleInputEvent(
       const blink::WebInputEvent& input_event) override;
   void BeginFrame(const cc::BeginFrameArgs& args) override;
   bool OnMessageReceived(const IPC::Message& message) override;
   void DidBecomeCurrent() override;
 
  private:
+  class ScopedSendZeroMemory;
+  struct SharedMemoryWithSize;
+  friend class ScopedSetZeroMemory;
   friend class SynchronousCompositorBase;
+
   SynchronousCompositorHost(RenderWidgetHostViewAndroid* rwhva,
                             SynchronousCompositorClient* client);
   void PopulateCommonParams(SyncCompositorCommonBrowserParams* params);
   void ProcessCommonParams(const SyncCompositorCommonRendererParams& params);
   void UpdateNeedsBeginFrames();
   void UpdateFrameMetaData(const cc::CompositorFrameMetadata& frame_metadata);
   void OnOverScroll(const SyncCompositorCommonRendererParams& params,
                     const DidOverscrollParams& over_scroll_params);
   void SendAsyncCompositorStateIfNeeded();
   void UpdateStateTask();
+  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 routing_id_;
   IPC::Sender* const sender_;
 
   bool is_active_;
   size_t bytes_limit_;
   cc::ReturnedResourceArray returned_resources_;
+  scoped_ptr<SharedMemoryWithSize> software_draw_shm_;
 
   // Updated by both renderer and browser.
   gfx::ScrollOffset root_scroll_offset_;
   bool root_scroll_offset_updated_by_browser_;
 
   // From renderer.
   uint32_t renderer_param_version_;
   bool need_animate_scroll_;
   bool need_invalidate_;
   bool need_begin_frame_;
   bool did_activate_pending_tree_;
 
   base::WeakPtrFactory<SynchronousCompositorHost> weak_ptr_factory_;
   DISALLOW_COPY_AND_ASSIGN(SynchronousCompositorHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_HOST_H_