Make WindowReachedScreen support async readback

content/browser/renderer_host/render_widget_host_impl.h

 // Copyright (c) 2012 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_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_
 
 #include <deque>
 #include <list>
 #include <map>
@@ skipping 529 matching lines @@
 
   // Returns the ID that uniquely describes this component to the latency
   // subsystem.
   int64 GetLatencyComponentId();
 
   static void CompositorFrameDrawn(const ui::LatencyInfo& latency_info);
 
   // Don't check whether we expected a resize ack during layout tests.
   static void DisableResizeAckCheckForTesting();
 
+  void WindowSnapshotAsyncCallback(
+      int routing_id,
+      int snapshot_id,
+      gfx::Size snapshot_size,
+      scoped_refptr<base::RefCountedBytes> png_data);
+
  protected:
   virtual RenderWidgetHostImpl* AsRenderWidgetHostImpl() OVERRIDE;
 
   // Create a LatencyInfo struct with INPUT_EVENT_LATENCY_RWH_COMPONENT
   // component if it is not already in |original|. And if |original| is
   // not NULL, it is also merged into the resulting LatencyInfo.
   ui::LatencyInfo CreateRWHLatencyInfoIfNotExist(
       const ui::LatencyInfo* original, blink::WebInputEvent::Type type);
 
   // Called when we receive a notification indicating that the renderer
@@ skipping 362 matching lines @@
   int64 last_input_number_;
 
   BrowserRenderingStats rendering_stats_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_IMPL_H_