mix-blend-mode implementation for accelerated layers

cc/layers/layer.h

Index: cc/layers/layer.h
diff --git a/cc/layers/layer.h b/cc/layers/layer.h
index 737e83df0671bb0a73883ebec880df5960276cf4..209228b7ffb33e6d3247a3a87389aa5e0ee090aa 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -121,6 +121,18 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   bool OpacityIsAnimating() const;
   virtual bool OpacityCanAnimateOnImplThread() const;
 
+  void SetBlendMode(SkXfermode::Mode blendMode);
+  SkXfermode::Mode blend_mode() const { return blend_mode_; }
+
+  bool has_blend_mode() const {
+    return blend_mode_ != SkXfermode::kSrcOver_Mode;
+  }
+
+  void SetIsRootForIsolatedGroup(bool root);
+  bool is_root_for_isolated_group() const {
+    return is_root_for_isolated_group_;
+  }
+
   void SetFilters(const FilterOperations& filters);
   const FilterOperations& filters() const { return filters_; }
 
@@ -543,6 +555,8 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   SkColor background_color_;
   CompositingReasons compositing_reasons_;
   float opacity_;
+  SkXfermode::Mode blend_mode_;
+  bool is_root_for_isolated_group_;
   skia::RefPtr<SkImageFilter> filter_;
   FilterOperations filters_;
   FilterOperations background_filters_;