Fix black background when locking with fullscreen window:

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/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/time.h"
 #include "ui/base/animation/animation_container_element.h"
+#include "ui/base/animation/animation_container_test_helper.h"
 #include "ui/base/animation/tween.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/compositor/layer_animation_element.h"
 
 namespace gfx {
 class Rect;
 class Transform;
 }
 
 namespace ui {
@@ skipping 159 matching lines @@
 
   // When set to true, all animations complete immediately.
   static void set_disable_animations_for_test(bool disable_animations) {
     disable_animations_for_test_ = disable_animations;
   }
 
   static bool disable_animations_for_test() {
     return disable_animations_for_test_;
   }
 
+  // Creates AnimationContainerTestHelper that would give fine control over
+  // animation progress. Other test flags (disable_animations_for_test /
+  // disable_timer_for_test) should be turned off.
+  static scoped_ptr<test::AnimationContainerTestHelper>
+    CreateAnimatorHelperForTest();
+
  protected:
   virtual ~LayerAnimator();
 
   LayerAnimationDelegate* delegate() { return delegate_; }
   const LayerAnimationDelegate* delegate() const { return delegate_; }
 
   // Virtual for testing.
   virtual void ProgressAnimation(LayerAnimationSequence* sequence,
                                  base::TimeDelta delta);
 
@@ skipping 150 matching lines @@
   // Observers are notified when layer animations end, are scheduled or are
   // aborted.
   ObserverList<LayerAnimationObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimator);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATOR_H_