CC Animations: Establish AnimationHost, AnimationTimeline and AnimationPlayer

cc/layers/layer.cc

 // Copyright 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/layer.h"
 
 #include <algorithm>
 
 #include "base/atomic_sequence_num.h"
 #include "base/location.h"
@@ skipping 111 matching lines @@
   if (replica_layer_.get()) {
     DCHECK_EQ(this, replica_layer_->parent());
     replica_layer_->RemoveFromParent();
   }
 }
 
 void Layer::SetLayerTreeHost(LayerTreeHost* host) {
   if (layer_tree_host_ == host)
     return;
 
-  if (layer_tree_host_)
+  if (layer_tree_host_) {
     layer_tree_host_->property_trees()->needs_rebuild = true;
-
-  if (host)
+    layer_tree_host_->UnregisterLayer(this);
+  }
+  if (host) {
     host->property_trees()->needs_rebuild = true;
+    host->RegisterLayer(this);
+  }
 
   InvalidatePropertyTreesIndices();
 
   layer_tree_host_ = host;
 
   // When changing hosts, the layer needs to commit its properties to the impl
   // side for the new host.
   SetNeedsPushProperties();
 
   for (size_t i = 0; i < children_.size(); ++i)
@@ skipping 1505 matching lines @@
           ? layer_tree_host()->meta_information_sequence_number()
           : 0;
 }
 
 bool Layer::sorted_for_recursion() {
   return sorted_for_recursion_tracker_ ==
          layer_tree_host()->meta_information_sequence_number();
 }
 
 }  // namespace cc