Pinch/Zoom Infrastructure & Plumbing CL

cc/trees/tree_synchronizer.cc

Index: cc/trees/tree_synchronizer.cc
diff --git a/cc/trees/tree_synchronizer.cc b/cc/trees/tree_synchronizer.cc
index 48a9d5bd966e35bb9ca6e8dafc797efde999d537..651aaed7997eb9ae58a004bf7df4813dc4f54171 100644
--- a/cc/trees/tree_synchronizer.cc
+++ b/cc/trees/tree_synchronizer.cc
@@ -25,6 +25,13 @@ void CollectExistingLayerImplRecursive(ScopedPtrLayerImplMap* old_layers,
   if (!layer_impl)
     return;
 
+  layer_impl->ClearScrollbars();
+  if (ScrollbarLayerImplBase* scrollbar_layer =
+          layer_impl->ToScrollbarLayer()) {
+    scrollbar_layer->ClearClipLayer();
+    scrollbar_layer->ClearScrollLayer();
+  }
+
   OwnedLayerImplList& children = layer_impl->children();
   for (OwnedLayerImplList::iterator it = children.begin();
        it != children.end();
@@ -54,8 +61,6 @@ scoped_ptr<LayerImpl> SynchronizeTreesInternal(
   scoped_ptr<LayerImpl> new_tree = SynchronizeTreesRecursive(
       &new_layers, &old_layers, layer_root, tree_impl);
 
-  UpdateScrollbarLayerPointersRecursive(&new_layers, layer_root);
-
   return new_tree.Pass();
 }
 
@@ -112,11 +117,6 @@ scoped_ptr<LayerImpl> SynchronizeTreesRecursiveInternal(
   layer_impl->SetReplicaLayer(SynchronizeTreesRecursiveInternal(
       new_layers, old_layers, layer->replica_layer(), tree_impl));
 
-  // Remove all dangling pointers. The pointers will be setup later in
-  // UpdateScrollbarLayerPointersRecursive phase
-  layer_impl->SetHorizontalScrollbarLayer(NULL);
-  layer_impl->SetVerticalScrollbarLayer(NULL);
-
   return layer_impl.Pass();
 }
 
@@ -138,54 +138,6 @@ scoped_ptr<LayerImpl> SynchronizeTreesRecursive(
       new_layers, old_layers, layer, tree_impl);
 }
 
-template <typename LayerType, typename ScrollbarLayerType>
-void UpdateScrollbarLayerPointersRecursiveInternal(
-    const RawPtrLayerImplMap* new_layers,
-    LayerType* layer) {
-  if (!layer)
-    return;
-
-  for (size_t i = 0; i < layer->children().size(); ++i) {
-    UpdateScrollbarLayerPointersRecursiveInternal<
-        LayerType, ScrollbarLayerType>(new_layers, layer->child_at(i));
-  }
-
-  ScrollbarLayerType* scrollbar_layer = layer->ToScrollbarLayer();
-  if (!scrollbar_layer)
-    return;
-
-  RawPtrLayerImplMap::const_iterator iter =
-      new_layers->find(layer->id());
-  ScrollbarLayerImplBase* scrollbar_layer_impl =
-      iter != new_layers->end()
-          ? static_cast<ScrollbarLayerImplBase*>(iter->second)
-          : NULL;
-  iter = new_layers->find(scrollbar_layer->ScrollLayerId());
-  LayerImpl* scroll_layer_impl =
-      iter != new_layers->end() ? iter->second : NULL;
-
-  DCHECK(scrollbar_layer_impl);
-  DCHECK(scroll_layer_impl);
-
-  if (scrollbar_layer->orientation() == HORIZONTAL)
-    scroll_layer_impl->SetHorizontalScrollbarLayer(scrollbar_layer_impl);
-  else
-    scroll_layer_impl->SetVerticalScrollbarLayer(scrollbar_layer_impl);
-}
-
-void UpdateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap* new_layers,
-                                           Layer* layer) {
-  UpdateScrollbarLayerPointersRecursiveInternal<Layer, ScrollbarLayerInterface>(
-      new_layers, layer);
-}
-
-void UpdateScrollbarLayerPointersRecursive(const RawPtrLayerImplMap* new_layers,
-                                           LayerImpl* layer) {
-  UpdateScrollbarLayerPointersRecursiveInternal<
-      LayerImpl,
-      ScrollbarLayerImplBase>(new_layers, layer);
-}
-
 // static
 void TreeSynchronizer::SetNumDependentsNeedPushProperties(
     Layer* layer, size_t num) {