sync compositor: Signal async frame on IO thread

android_webview/browser/render_thread_manager.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_RENDER_THREAD_MANAGER_H_
 #define ANDROID_WEBVIEW_BROWSER_RENDER_THREAD_MANAGER_H_
 
 #include <map>
 
 #include "android_webview/browser/compositor_frame_consumer.h"
@@ skipping 42 matching lines @@
           frame_future) override;
   void InitializeHardwareDrawIfNeededOnUI() override;
   ParentCompositorDrawConstraints GetParentDrawConstraintsOnUI() const override;
   void SwapReturnedResourcesOnUI(
       ReturnedResourcesMap* returned_resource_map) override;
   bool ReturnedResourcesEmptyOnUI() const override;
   std::unique_ptr<ChildFrame> PassUncommittedFrameOnUI() override;
   bool HasFrameOnUI() const override;
   void DeleteHardwareRendererOnUI() override;
 
-  // RT thread methods.
+  // Render thread methods.
   gfx::Vector2d GetScrollOffsetOnRT();
   std::unique_ptr<ChildFrame> PassFrameOnRT();
+  scoped_refptr<content::SynchronousCompositor::FrameFuture>
+  PassFrameFutureOnRT();
   void DrawGL(AwDrawGLInfo* draw_info);
   void PostExternalDrawConstraintsToChildCompositorOnRT(
       const ParentCompositorDrawConstraints& parent_draw_constraints);
   void InsertReturnedResourcesOnRT(const cc::ReturnedResourceArray& resources,
                                    const CompositorID& compositor_id,
                                    uint32_t compositor_frame_sink_id);
 
  private:
   friend class internal::RequestInvokeGLTracker;
   class InsideHardwareReleaseReset {
@@ skipping 46 matching lines @@
   base::Closure request_draw_gl_closure_;
 
   base::WeakPtrFactory<RenderThreadManager> weak_factory_on_ui_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderThreadManager);
 };
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_RENDER_THREAD_MANAGER_H_