mix-blend-mode implementation for accelerated layers

cc/output/gl_renderer.h

Index: cc/output/gl_renderer.h
diff --git a/cc/output/gl_renderer.h b/cc/output/gl_renderer.h
index bc47870063d0e588800f0a699b1cfc11aefd42fe..d6a7c6195172660855ee54bbac3bd9f759706a33 100644
--- a/cc/output/gl_renderer.h
+++ b/cc/output/gl_renderer.h
@@ -104,6 +104,8 @@ class CC_EXPORT GLRenderer : public DirectRenderer {
   void GetFramebufferTexture(unsigned texture_id,
                              ResourceFormat texture_format,
                              gfx::Rect device_rect);
+  void GetFramebufferTextureSubImage(unsigned texture_id,
+                                     gfx::Rect device_rect);
   void ReleaseRenderPassTextures();
 
   void SetStencilEnabled(bool enabled);
@@ -153,11 +155,12 @@ class CC_EXPORT GLRenderer : public DirectRenderer {
                             const CheckerboardDrawQuad* quad);
   void DrawDebugBorderQuad(const DrawingFrame* frame,
                            const DebugBorderDrawQuad* quad);
-  scoped_ptr<ScopedResource> DrawBackgroundFilters(
+  scoped_ptr<ScopedResource> GetBackgroundWithFilters(
       DrawingFrame* frame,
       const RenderPassDrawQuad* quad,
       const gfx::Transform& contents_device_transform,
-      const gfx::Transform& contents_device_transformInverse);
+      const gfx::Transform& contents_device_transformInverse,
+      bool* background_changed);
   void DrawRenderPassQuad(DrawingFrame* frame, const RenderPassDrawQuad* quad);
   void DrawSolidColorQuad(const DrawingFrame* frame,
                           const SolidColorDrawQuad* quad);