Add support for tagging layers.

cc/layer.h

Index: cc/layer.h
diff --git a/cc/layer.h b/cc/layer.h
index e7df4c08417438213d18838adcc177e5d440b765..de7d427d2dc72875f43b8414856ab866571cb7c6 100644
--- a/cc/layer.h
+++ b/cc/layer.h
@@ -52,6 +52,12 @@ class CC_EXPORT Layer : public base::RefCounted<Layer>,
 public:
     typedef std::vector<scoped_refptr<Layer> > LayerList;
 
+    enum Tag {
+        kTagNone = 0x00,
+        kTagNonCompositedContentHost = 0x01,
+        kTagIgnoreForContinuousRepaints = 0x02,
+    };
+
     static scoped_refptr<Layer> create();
 
     int id() const;
@@ -284,6 +290,11 @@ public:
 
     gfx::Rect layerRectToContentRect(const gfx::RectF& layerRect) const;
 
+    void setTags(unsigned int tags);
+    unsigned int getTags() const;
+    void addTag(Tag tag);
+    bool getTag(Tag tag) const;
+
     // In impl-side painting, this returns true if this layer type is not
     // compatible with the main thread running freely, such as a double-buffered
     // canvas that doesn't want to be triple-buffered across all three trees.
@@ -401,6 +412,8 @@ private:
     WebKit::WebLayerScrollClient* m_layerScrollClient;
 
     DrawProperties<Layer, RenderSurface> m_drawProperties;
+
+    unsigned int m_tags;
 };
 
 void sortLayers(std::vector<scoped_refptr<Layer> >::iterator, std::vector<scoped_refptr<Layer> >::iterator, void*);