Eliminate ash::internal namespace

ash/shelf/background_animator.h

Index: ash/shelf/background_animator.h
diff --git a/ash/shelf/background_animator.h b/ash/shelf/background_animator.h
index 805f7d5e5d2795b1b48767c17577a994d43d4281..37be3be56d9d7d13cdc32f67e8997962c2c73cb9 100644
--- a/ash/shelf/background_animator.h
+++ b/ash/shelf/background_animator.h
@@ -18,8 +18,6 @@ enum BackgroundAnimatorChangeType {
   BACKGROUND_CHANGE_IMMEDIATE
 };
 
-namespace internal {
-
 // Delegate is notified any time the background changes.
 class ASH_EXPORT BackgroundAnimatorDelegate {
  public:
@@ -69,7 +67,6 @@ class ASH_EXPORT BackgroundAnimator : public gfx::AnimationDelegate {
   DISALLOW_COPY_AND_ASSIGN(BackgroundAnimator);
 };
 
-}  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SHELF_BACKGROUND_ANIMATOR_H_