sync compositor: Signal async frame on IO thread

content/public/browser/android/synchronous_compositor.h

 // Copyright 2013 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_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_H_
 #define CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_H_
 
 #include <stddef.h>
 
 #include <memory>
@@ skipping 68 matching lines @@
 
   // "On demand" hardware draw. Parameters are used by compositor for this draw.
   // |viewport_size| is the current size to improve results during resize.
   // |viewport_rect_for_tile_priority| and |transform_for_tile_priority| are
   // used to customize the tiling decisions of compositor.
   virtual Frame DemandDrawHw(
       const gfx::Size& viewport_size,
       const gfx::Rect& viewport_rect_for_tile_priority,
       const gfx::Transform& transform_for_tile_priority) = 0;
 
-  // Same as DemandDrawHw, but uses asynchronous IPC messages. Calls
-  // SynchronousCompositorClient::OnDrawHardwareProcessFrame to return the
-  // frame.
-  virtual void DemandDrawHwAsync(
+  // Same as DemandDrawHw, but uses asynchronous IPC messages.
+  virtual scoped_refptr<FrameFuture> DemandDrawHwAsync(
       const gfx::Size& viewport_size,
       const gfx::Rect& viewport_rect_for_tile_priority,
       const gfx::Transform& transform_for_tile_priority) = 0;
 
   // For delegated rendering, return resources from parent compositor to this.
   // Note that all resources must be returned before ReleaseHwDraw.
   virtual void ReturnResources(uint32_t compositor_frame_sink_id,
                                const cc::ReturnedResourceArray& resources) = 0;
 
   // "On demand" SW draw, into the supplied canvas (observing the transform
@@ skipping 17 matching lines @@
   // and if any input animation is active, it should tick now.
   virtual void OnComputeScroll(base::TimeTicks animation_time) = 0;
 
  protected:
   virtual ~SynchronousCompositor() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_ANDROID_SYNCHRONOUS_COMPOSITOR_H_