Animating docked background in sync with shelf

ash/shelf/background_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 ASH_SHELF_BACKGROUND_ANIMATOR_H_
 #define ASH_SHELF_BACKGROUND_ANIMATOR_H_
 
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/gfx/animation/slide_animation.h"
 
 namespace ash {
+
+// How the background can be changed.
+enum BackgroundAnimatorChangeType {
+  BACKGROUND_CHANGE_ANIMATE,
+  BACKGROUND_CHANGE_IMMEDIATE
+};
+
 namespace internal {
 
 // Delegate is notified any time the background changes.
 class ASH_EXPORT BackgroundAnimatorDelegate {
  public:
   virtual void UpdateBackground(int alpha) = 0;
 
  protected:
   virtual ~BackgroundAnimatorDelegate() {}
 };
 
 // BackgroundAnimator is used by the shelf to animate the background (alpha).
 class ASH_EXPORT BackgroundAnimator : public gfx::AnimationDelegate {
  public:
-  // How the background can be changed.
-  enum ChangeType {
-    CHANGE_ANIMATE,
-    CHANGE_IMMEDIATE
-  };
-
   BackgroundAnimator(BackgroundAnimatorDelegate* delegate,
                      int min_alpha,
                      int max_alpha);
   virtual ~BackgroundAnimator();
 
   // Sets the transition time in ms.
   void SetDuration(int time_in_ms);
 
   // Sets whether a background is rendered. Initial value is false. If |type|
   // is |CHANGE_IMMEDIATE| and an animation is not in progress this notifies
   // the delegate immediately (synchronously from this method).
-  void SetPaintsBackground(bool value, ChangeType type);
+  void SetPaintsBackground(bool value, BackgroundAnimatorChangeType type);
   bool paints_background() const { return paints_background_; }
 
   // Current alpha.
   int alpha() const { return alpha_; }
 
   // gfx::AnimationDelegate overrides:
   virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE;
 
  private:
   BackgroundAnimatorDelegate* delegate_;
 
   const int min_alpha_;
   const int max_alpha_;
 
   gfx::SlideAnimation animation_;
 
   // Whether the background is painted.
   bool paints_background_;
 
   // Current alpha value of the background.
   int alpha_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundAnimator);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SHELF_BACKGROUND_ANIMATOR_H_