cc: Replace Pass() with std::move() in some subdirs.

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 4ecf5d3c95763604f6203427a4f3eb70bcd61fed..993514716e115556d71103fa48bffe2ac12ddcbc 100644
--- a/cc/trees/tree_synchronizer.cc
+++ b/cc/trees/tree_synchronizer.cc
@@ -32,7 +32,7 @@ void CollectExistingLayerImplRecursive(ScopedPtrLayerImplMap* old_layers,
   CollectExistingLayerImplRecursive(old_layers, layer_impl->TakeReplicaLayer());
 
   int id = layer_impl->id();
-  old_layers->set(id, layer_impl.Pass());
+  old_layers->set(id, std::move(layer_impl));
 }
 
 template <typename LayerType>
@@ -46,28 +46,29 @@ scoped_ptr<LayerImpl> SynchronizeTreesInternal(
   ScopedPtrLayerImplMap old_layers;
   RawPtrLayerImplMap new_layers;
 
-  CollectExistingLayerImplRecursive(&old_layers, old_layer_impl_root.Pass());
+  CollectExistingLayerImplRecursive(&old_layers,
+                                    std::move(old_layer_impl_root));
 
   scoped_ptr<LayerImpl> new_tree = SynchronizeTreesRecursive(
       &new_layers, &old_layers, layer_root, tree_impl);
 
-  return new_tree.Pass();
+  return new_tree;
 }
 
 scoped_ptr<LayerImpl> TreeSynchronizer::SynchronizeTrees(
     Layer* layer_root,
     scoped_ptr<LayerImpl> old_layer_impl_root,
     LayerTreeImpl* tree_impl) {
-  return SynchronizeTreesInternal(
-      layer_root, old_layer_impl_root.Pass(), tree_impl);
+  return SynchronizeTreesInternal(layer_root, std::move(old_layer_impl_root),
+                                  tree_impl);
 }
 
 scoped_ptr<LayerImpl> TreeSynchronizer::SynchronizeTrees(
     LayerImpl* layer_root,
     scoped_ptr<LayerImpl> old_layer_impl_root,
     LayerTreeImpl* tree_impl) {
-  return SynchronizeTreesInternal(
-      layer_root, old_layer_impl_root.Pass(), tree_impl);
+  return SynchronizeTreesInternal(layer_root, std::move(old_layer_impl_root),
+                                  tree_impl);
 }
 
 template <typename LayerType>
@@ -81,7 +82,7 @@ scoped_ptr<LayerImpl> ReuseOrCreateLayerImpl(RawPtrLayerImplMap* new_layers,
     layer_impl = layer->CreateLayerImpl(tree_impl);
 
   (*new_layers)[layer->id()] = layer_impl.get();
-  return layer_impl.Pass();
+  return layer_impl;
 }
 
 template <typename LayerType>
@@ -107,7 +108,7 @@ scoped_ptr<LayerImpl> SynchronizeTreesRecursiveInternal(
   layer_impl->SetReplicaLayer(SynchronizeTreesRecursiveInternal(
       new_layers, old_layers, layer->replica_layer(), tree_impl));
 
-  return layer_impl.Pass();
+  return layer_impl;
 }
 
 scoped_ptr<LayerImpl> SynchronizeTreesRecursive(