cc: Make async readback path use async glRreadPixels.

cc/output/software_renderer.h

 // Copyright 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 CC_OUTPUT_SOFTWARE_RENDERER_H_
 #define CC_OUTPUT_SOFTWARE_RENDERER_H_
 
 #include "base/basictypes.h"
 #include "cc/base/cc_export.h"
 #include "cc/output/compositor_frame.h"
@@ skipping 40 matching lines @@
       gfx::Rect framebuffer_rect) OVERRIDE;
   virtual void SetDrawViewportSize(gfx::Size viewport_size) OVERRIDE;
   virtual void SetScissorTestRect(gfx::Rect scissor_rect) OVERRIDE;
   virtual void ClearFramebuffer(DrawingFrame* frame) OVERRIDE;
   virtual void DoDrawQuad(DrawingFrame* frame, const DrawQuad* quad) OVERRIDE;
   virtual void BeginDrawingFrame(DrawingFrame* frame) OVERRIDE;
   virtual void FinishDrawingFrame(DrawingFrame* frame) OVERRIDE;
   virtual bool FlippedFramebuffer() const OVERRIDE;
   virtual void EnsureScissorTestEnabled() OVERRIDE;
   virtual void EnsureScissorTestDisabled() OVERRIDE;
-  virtual void CopyCurrentRenderPassToBitmap(DrawingFrame* frame,
-                                             SkBitmap* bitmap) OVERRIDE;
+  virtual void CopyCurrentRenderPassToBitmap(
+      DrawingFrame* frame,
+      const CopyRenderPassCallback& callback) OVERRIDE;
 
  private:
   SoftwareRenderer(
       RendererClient* client,
       OutputSurface* output_surface,
       ResourceProvider* resource_provider);
 
   void ClearCanvas(SkColor color);
   void SetClipRect(gfx::Rect rect);
   bool IsSoftwareResource(ResourceProvider::ResourceId resource_id) const;
@@ skipping 25 matching lines @@
   scoped_ptr<ResourceProvider::ScopedWriteLockSoftware>
       current_framebuffer_lock_;
   CompositorFrame compositor_frame_;
 
   DISALLOW_COPY_AND_ASSIGN(SoftwareRenderer);
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_SOFTWARE_RENDERER_H_