cc: Add id->LayerImpl map to LayerTreeImpl

cc/tree_synchronizer.cc

Index: cc/tree_synchronizer.cc
diff --git a/cc/tree_synchronizer.cc b/cc/tree_synchronizer.cc
index 8f62f9bbb7796eeb32257a6173ec3526d5e1f853..17f237a467001b8819c88d33e3be5948880d6bf5 100644
--- a/cc/tree_synchronizer.cc
+++ b/cc/tree_synchronizer.cc
@@ -37,8 +37,8 @@ void TreeSynchronizer::collectExistingLayerImplRecursive(ScopedPtrLayerImplMap&
     for (size_t i = 0; i < children.size(); ++i)
         collectExistingLayerImplRecursive(oldLayers, children.take(i));
 
-    collectExistingLayerImplRecursive(oldLayers, layerImpl->m_maskLayer.Pass());
-    collectExistingLayerImplRecursive(oldLayers, layerImpl->m_replicaLayer.Pass());
+    collectExistingLayerImplRecursive(oldLayers, layerImpl->takeMaskLayer());
+    collectExistingLayerImplRecursive(oldLayers, layerImpl->takeReplicaLayer());
 
     int id = layerImpl->id();
     oldLayers.set(id, layerImpl.Pass());