MacViews: Overlay Scrollbars with Show/Hide Animations

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>
 
@@ skipping 87 matching lines @@
   float GetTargetGrayscale() const;
 
   // Sets the color on the delegate. May cause an implicit animation.
   virtual void SetColor(SkColor color);
   SkColor GetTargetColor() const;
 
   // Returns the default length of animations, including adjustment for slow
   // 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
   // a valid delegate installed.
   void SetDelegate(LayerAnimationDelegate* delegate);
 
   // Unsubscribe from |cc_layer_| and subscribe to |new_layer|.
   void SwitchToLayer(scoped_refptr<cc::Layer> new_layer);
 
   // Attach AnimationPlayer to Layer and AnimationTimeline
@@ skipping 200 matching lines @@
   bool StartSequenceImmediately(LayerAnimationSequence* sequence);
 
   // Sets the value of target as if all the running and queued animations were
   // allowed to finish.
   void GetTargetValue(LayerAnimationElement::TargetValue* target) const;
 
   // Called whenever an animation is added to the animation queue. Either by
   // 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();
 
   // Cleans up any running animations that may have been deleted.
   void PurgeDeletedAnimations();
 
   LayerAnimatorCollection* GetLayerAnimatorCollection();
 
   // LayerAnimationEventObserver
@@ skipping 48 matching lines @@
   // Observers are notified when layer animations end, are scheduled or are
   // aborted.
   base::ObserverList<LayerAnimationObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerAnimator);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATOR_H_