sync compositor: Signal async frame on IO thread

android_webview/browser/hardware_renderer.h

 // Copyright 2014 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 ANDROID_WEBVIEW_BROWSER_HARDWARE_RENDERER_H_
 #define ANDROID_WEBVIEW_BROWSER_HARDWARE_RENDERER_H_
 
 #include <memory>
 
 #include "android_webview/browser/compositor_id.h"
 #include "base/macros.h"
+#include "base/memory/ptr_util.h"

[dcheng, 2016/10/21 06:42:56]

Nit: let's not include this in headers (it's pretty rare for a header to
actually need this)

[boliu, 2016/10/21 15:15:32]

Done.

 #include "base/memory/ref_counted.h"
 #include "cc/surfaces/frame_sink_id.h"
 #include "cc/surfaces/surface_factory_client.h"
 #include "cc/surfaces/surface_id.h"
+#include "content/public/browser/android/synchronous_compositor.h"
 
 struct AwDrawGLInfo;
 
 namespace cc {
 class Display;
 class SurfaceFactory;
 class SurfaceIdAllocator;
 class SurfaceManager;
 }
 
@@ skipping 33 matching lines @@
   gfx::Size frame_size_;
 
   // Infromation from UI on last commit.
   gfx::Vector2d scroll_offset_;
 
   // This holds the last ChildFrame received. Contains the frame info of the
   // last frame. The |frame| member may be null if it's already submitted to
   // SurfaceFactory.
   std::unique_ptr<ChildFrame> child_frame_;
 
+  scoped_refptr<content::SynchronousCompositor::FrameFuture> frame_future_;
+
   const scoped_refptr<SurfacesInstance> surfaces_;
   cc::FrameSinkId frame_sink_id_;
   const std::unique_ptr<cc::SurfaceIdAllocator> surface_id_allocator_;
   std::unique_ptr<cc::SurfaceFactory> surface_factory_;
   cc::LocalFrameId child_id_;
   CompositorID compositor_id_;
   // HardwareRenderer guarantees resources are returned in the order of
   // compositor_frame_sink_id, and resources for old output surfaces are
   // dropped.
   uint32_t last_committed_compositor_frame_sink_id_;
   uint32_t last_submitted_compositor_frame_sink_id_;
 
   DISALLOW_COPY_AND_ASSIGN(HardwareRenderer);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_HARDWARE_RENDERER_H_