UI Compositor: Fix threaded animation survival if layer removed and added.

ui/compositor/layer_animator.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_ANIMATOR_H_
 #define UI_COMPOSITOR_LAYER_ANIMATOR_H_
 
 #include <deque>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/time/time.h"
 #include "cc/animation/layer_animation_event_observer.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/compositor/layer_animation_element.h"
 #include "ui/compositor/layer_threaded_animation_delegate.h"
 #include "ui/gfx/animation/tween.h"
 
 namespace cc {
 class Animation;
 class AnimationPlayer;
 class AnimationTimeline;
 class Layer;
+class LayerAnimationController;
 }
 
 namespace gfx {
 class Animation;
 class Rect;
 class Transform;
 }
 
 namespace ui {
 class Compositor;
@@ skipping 345 matching lines @@
   bool disable_timer_for_test_;
 
   // Prevents timer adjustments in case when we start multiple animations
   // with preemption strategies that discard previous animations.
   bool adding_animations_;
 
   // Observers are notified when layer animations end, are scheduled or are
   // aborted.
   base::ObserverList<LayerAnimationObserver> observers_;
 
+  // We store a state of LayerAnimationController here to save it in
+  // ResetCompositor/SetCompositor scope.
+  // TODO(loyso): Remove it. crbug.com/592873.
+  scoped_refptr<cc::LayerAnimationController> animation_controller_state_;
+
   DISALLOW_COPY_AND_ASSIGN(LayerAnimator);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATOR_H_