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 889e09ba0bbec7ef01e77d1afd7603aef1c14596..499c1666a29d99148a121f38c4d5af693c1789d4 100644
--- a/cc/layers/layer.h
+++ b/cc/layers/layer.h
@@ -126,6 +126,18 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   bool OpacityIsAnimating() const;
   virtual bool OpacityCanAnimateOnImplThread() const;
 
+  void SetBlendMode(SkXfermode::Mode blend_mode);
+  SkXfermode::Mode blend_mode() const { return blend_mode_; }
+
+  bool uses_default_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_; }
   bool FilterIsAnimating() const;
@@ -459,6 +471,9 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
   // unused resources on the impl thread are returned before commit completes.
   void SetNextCommitWaitsForActivation();
 
+  // Called when the blend mode or filters have been changed
+  void SetNeedsFilterContextIfNeeded();
+
   void SetNeedsPushProperties();
   void AddDependentNeedsPushProperties();
   void RemoveDependentNeedsPushProperties();
@@ -551,6 +566,8 @@ 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_;
   FilterOperations filters_;
   FilterOperations background_filters_;
   float anchor_point_z_;