MacViews: Overlay Scrollbars with Show/Hide Animations

ui/compositor/layer_animator.h

Index: ui/compositor/layer_animator.h
diff --git a/ui/compositor/layer_animator.h b/ui/compositor/layer_animator.h
index 655c17c9b3bf273bcffd23d2baff5b830e6199f0..c6c4aff1dbe07e643a467a2eaeb3a579a9efa384 100644
--- a/ui/compositor/layer_animator.h
+++ b/ui/compositor/layer_animator.h
@@ -105,6 +105,9 @@ class COMPOSITOR_EXPORT LayerAnimator
   // animation mode if set.
   base::TimeDelta GetTransitionDuration() const;
 
+  // Sets |transition_duration_| unless |is_transition_duration_locked_| is set.
+  void SetTransitionDuration(base::TimeDelta duration);

[tapted, 2016/02/16 06:47:58]

Ah curious. So I think the way this is intended to be used is something like (in
HideScrollbar())

ui::ScopedLayerAnimationSettings animation(layer()->GetAnimator());
animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(kFadeDurationMs));

then this doesn't need to be moved into the public interface

[spqchan, 2016/02/16 23:18:18]

Ah, that makes more sense. I made the change for it

+
   // Sets the layer animation delegate the animator is associated with. The
   // animator does not own the delegate. The layer animator expects a non-NULL
   // delegate for most of its operations, so do not call any methods without
@@ -325,9 +328,6 @@ class COMPOSITOR_EXPORT LayerAnimator
   // starting the animation or adding to the queue.
   void OnScheduled(LayerAnimationSequence* sequence);
 
-  // Sets |transition_duration_| unless |is_transition_duration_locked_| is set.
-  void SetTransitionDuration(base::TimeDelta duration);
-
   // Clears the animation queues and notifies any running animations that they
   // have been aborted.
   void ClearAnimationsInternal();