mix-blend-mode implementation for accelerated layers

cc/layers/render_surface.h

Index: cc/layers/render_surface.h
diff --git a/cc/layers/render_surface.h b/cc/layers/render_surface.h
index adce0a8a2013961617b9197ebe32501d73c7b65a..674148fb0622e5a1003ba968ee0950bc1d74a1ed 100644
--- a/cc/layers/render_surface.h
+++ b/cc/layers/render_surface.h
@@ -35,6 +35,11 @@ class CC_EXPORT RenderSurface {
   void SetDrawOpacity(float opacity) { draw_opacity_ = opacity; }
   float draw_opacity() const { return draw_opacity_; }
 
+  void SetHasBlendMode(bool has_blend_mode) {
+    has_blend_mode_ = has_blend_mode;
+  }
+  bool has_blend_mode() const { return has_blend_mode_; }
+
   void SetDrawOpacityIsAnimating(bool draw_opacity_is_animating) {
     draw_opacity_is_animating_ = draw_opacity_is_animating;
   }
@@ -119,6 +124,7 @@ class CC_EXPORT RenderSurface {
 
   float draw_opacity_;
   bool draw_opacity_is_animating_;
+  bool has_blend_mode_;
   gfx::Transform draw_transform_;
   gfx::Transform screen_space_transform_;
   gfx::Transform replica_draw_transform_;