Implemented prototype for new ink drop specs.

ui/views/animation/ink_drop_animation_controller_factory.h

 // Copyright 2015 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_VIEWS_ANIMATION_INK_DROP_ANIMATION_CONTROLLER_FACTORY_H_
 #define UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_CONTROLLER_FACTORY_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
-#include "ui/views/animation/ink_drop_animation_controller.h"
 #include "ui/views/views_export.h"
 
 namespace views {
+class InkDropAnimationController;
+class InkDropHost;
 
 // A factory to create InkDropAnimationController. A different
 // InkDropAnimationController type will be created based on whether or not
 // material design is enabled.
 class VIEWS_EXPORT InkDropAnimationControllerFactory {
  public:
-  // Creates a new InkDropAnimationController.
+  // Creates a new InkDropAnimationController that will add/remove an
+  // InkDropAnimation's ui::Layer to/from the |ink_drop_host| when the animation
+  // is active/inactive.
   static scoped_ptr<InkDropAnimationController>
   CreateInkDropAnimationController(InkDropHost* ink_drop_host);
 
  private:
   InkDropAnimationControllerFactory();
   ~InkDropAnimationControllerFactory();
 
   DISALLOW_COPY_AND_ASSIGN(InkDropAnimationControllerFactory);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_ANIMATION_INK_DROP_ANIMATION_CONTROLLER_FACTORY_H_