Replace more ObserverList with base::ObserverList.

ui/compositor/layer_animation_sequence.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_COMPOSITOR_LAYER_ANIMATION_SEQUENCE_H_
 #define UI_COMPOSITOR_LAYER_ANIMATION_SEQUENCE_H_
 
 #include <vector>
 
 #include "base/gtest_prod_util.h"
@@ skipping 158 matching lines @@
   // least one of the sequences in this group has a threaded first element.
   bool waiting_for_group_start_;
 
   // Identifies groups of sequences that are supposed to start together.
   // Also used to identify the owner of a particular threaded animation; any
   // in-progress threaded animation owned by this sequence will have this
   // group id.
   int animation_group_id_;
 
   // These parties are notified when layer animations end.
-  ObserverList<LayerAnimationObserver> observers_;
+  base::ObserverList<LayerAnimationObserver> observers_;
 
   // Tracks the last_progressed_fraction() of the most recently progressed
   // element.
   double last_progressed_fraction_;
 
   base::WeakPtrFactory<LayerAnimationSequence> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimationSequence);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATION_SEQUENCE_H_