[ash-md] Fixed ShelfBackgroundAnimator to not snap target values when being preempted.

ash/common/shelf/shelf_background_animator.cc

Index: ash/common/shelf/shelf_background_animator.cc
diff --git a/ash/common/shelf/shelf_background_animator.cc b/ash/common/shelf/shelf_background_animator.cc
index ad0311e1fdc54591b70fe0015db9d04936416969..17a668220407fec8a293f8607b8b0e2404456ed6 100644
--- a/ash/common/shelf/shelf_background_animator.cc
+++ b/ash/common/shelf/shelf_background_animator.cc
@@ -98,14 +98,6 @@ void ShelfBackgroundAnimator::AnimationEnded(const gfx::Animation* animation) {
   animator_.reset();
 }
 
-void ShelfBackgroundAnimator::AnimationCanceled(
-    const gfx::Animation* animation) {
-  DCHECK_EQ(animation, animator_.get());
-  SetAnimationValues(animator_->IsShowing() ? 1.0 : 0.0);
-  // Animations are only cancelled when they are being pre-empted so we don't
-  // destroy the |animator_| because it may be re-used immediately.
-}
-
 void ShelfBackgroundAnimator::OnWallpaperDataChanged() {}
 
 void ShelfBackgroundAnimator::OnWallpaperColorsChanged() {