[ash-md] Animates ToggleButton highlight to move it in sync with the thumb

ui/views/controls/button/toggle_button.h

 // Copyright 2016 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_CONTROLS_BUTTON_TOGGLE_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_TOGGLE_BUTTON_H_
 
 #include "ui/gfx/animation/slide_animation.h"
 #include "ui/views/controls/button/custom_button.h"
 
 namespace views {
 
 // This view presents a button that has two states: on and off. This is similar
 // to a checkbox but has no text and looks more like a two-state horizontal
 // slider.
 class VIEWS_EXPORT ToggleButton : public CustomButton {
  public:
   explicit ToggleButton(ButtonListener* listener);
   ~ToggleButton() override;
 
   void SetIsOn(bool is_on, bool animate);
   bool is_on() const { return is_on_; }
 
  private:
+  class ThumbView;
+
   // CustomButton:
   gfx::Size GetPreferredSize() const override;
   void OnPaint(gfx::Canvas* canvas) override;
   void NotifyClick(const ui::Event& event) override;
   void OnNativeThemeChanged(const ui::NativeTheme* theme) override;
+  void AddInkDropLayer(ui::Layer* ink_drop_layer) override;
+  void RemoveInkDropLayer(ui::Layer* ink_drop_layer) override;
   std::unique_ptr<InkDropRipple> CreateInkDropRipple() const override;
   SkColor GetInkDropBaseColor() const override;
   bool ShouldShowInkDropHighlight() const override;
 
   // gfx::AnimationDelegate:
   void AnimationProgressed(const gfx::Animation* animation) override;
 
   // Calculates the bounding box for the thumb (the circle).
   gfx::Rect GetThumbBounds() const;
 
   bool is_on_;
   gfx::SlideAnimation slide_animation_;
 
+  // A view representing the thumb when ink drop animation is active.
+  std::unique_ptr<ThumbView> thumb_view_;
+
   DISALLOW_COPY_AND_ASSIGN(ToggleButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_TOGGLE_BUTTON_H_