Activate LayerImpl tree with sync+push instead of pointer swap

cc/tree_synchronizer.h

Index: cc/tree_synchronizer.h
diff --git a/cc/tree_synchronizer.h b/cc/tree_synchronizer.h
index 905931485586ee5bb3c0ffb119926004192c2507..d0349c0bee2c999a96d46c49d7ad4afbe09d58ee 100644
--- a/cc/tree_synchronizer.h
+++ b/cc/tree_synchronizer.h
@@ -21,23 +21,16 @@ public:
     // Accepts a Layer tree and returns a reference to a LayerImpl tree that duplicates the structure
     // of the Layer tree, reusing the LayerImpls in the tree provided by oldLayerImplRoot if possible.
     static scoped_ptr<LayerImpl> synchronizeTrees(Layer* layerRoot, scoped_ptr<LayerImpl> oldLayerImplRoot, LayerTreeImpl*);
+    static scoped_ptr<LayerImpl> synchronizeTrees(LayerImpl* layerRoot, scoped_ptr<LayerImpl> oldLayerImplRoot, LayerTreeImpl*);
 
-    // Pushes properties from a Layer tree to a structurally equivalent
+    // Pushes properties from a Layer or LayerImpl tree to a structurally equivalent
     // LayerImpl tree.
     static void pushProperties(Layer* layerRoot, LayerImpl* layerImplRoot);
+    static void pushProperties(LayerImpl* layerRoot, LayerImpl* layerImplRoot);
 
 private:
     TreeSynchronizer(); // Not instantiable.
 
-    typedef ScopedPtrHashMap<int, LayerImpl> ScopedPtrLayerImplMap;
-    typedef base::hash_map<int, LayerImpl*> RawPtrLayerImplMap;
-
-    // Declared as static member functions so they can access functions on Layer as a friend class.
-    static scoped_ptr<LayerImpl> reuseOrCreateLayerImpl(RawPtrLayerImplMap& newLayers, ScopedPtrLayerImplMap& oldLayers, Layer*, LayerTreeImpl*);
-    static void collectExistingLayerImplRecursive(ScopedPtrLayerImplMap& oldLayers, scoped_ptr<LayerImpl>);
-    static scoped_ptr<LayerImpl> synchronizeTreeRecursive(RawPtrLayerImplMap& newLayers, ScopedPtrLayerImplMap& oldLayers, Layer*, LayerTreeImpl*);
-    static void updateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap& newLayers, Layer*);
-
     DISALLOW_COPY_AND_ASSIGN(TreeSynchronizer);
 };