Revert 139494 - ash: Improved window maximize/restore animations

ui/compositor/layer_animation_observer.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_ANIMATION_OBSERVER_H_
 #define UI_COMPOSITOR_LAYER_ANIMATION_OBSERVER_H_
 #pragma once
 
 #include <set>
 
@@ skipping 65 matching lines @@
 
 // An implicit animation observer is intended to be used in conjunction with a
 // ScopedLayerAnimationSettings object in order to receive a notification when
 // all implicit animations complete.
 class COMPOSITOR_EXPORT ImplicitAnimationObserver
     : public LayerAnimationObserver {
  public:
   ImplicitAnimationObserver();
   virtual ~ImplicitAnimationObserver();
 
-  // Do not "delete this" in your implementation.  Consider using something
-  // like MessageLoop::current()->DeleteSoon() instead.
   virtual void OnImplicitAnimationsCompleted() = 0;
 
  protected:
   // Deactivates the observer and clears the collection of animations it is
   // waiting for.
   void StopObservingImplicitAnimations();
 
  private:
   friend class ScopedLayerAnimationSettings;
 
@@ skipping 14 matching lines @@
   void SetActive(bool active);
 
   void CheckCompleted();
 
   bool active_;
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_ANIMATION_OBSERVER_H_