Adding ripple effect for clicks on MD slider

ui/views/controls/slider.h

Index: ui/views/controls/slider.h
diff --git a/ui/views/controls/slider.h b/ui/views/controls/slider.h
index e90da3a4ab1ae20426f114e9c184a7dbd6d6bef5..22bb20cd2f3f78bc511cd4105c0253f52ad8e7c1 100644
--- a/ui/views/controls/slider.h
+++ b/ui/views/controls/slider.h
@@ -77,11 +77,19 @@ class VIEWS_EXPORT Slider : public View, public gfx::AnimationDelegate {
   // Returns the current position of the thumb on the slider.
   float GetAnimatingValue() const;
 
+  // Set to true to show the highlight of the thumb on the slider; and set to
+  // false to hide the effect.

[varkha, 2016/09/24 13:59:18]

nit: maybe just "Shows or hides the highlight on the slider thumb. The default
implantation does nothing.".

[yiyix, 2016/09/29 19:09:39]

I like that it points out the default implementation is empty.

+  virtual void SetHighlighted(bool is_highlighted);
+
   virtual int GetThumbWidth() = 0;

[varkha, 2016/09/24 13:59:18]

nit: doc?

[yiyix, 2016/09/29 19:09:39]

Done.

 
   // views::View:
   void OnPaint(gfx::Canvas* canvas) override;
 
+  // gfx::AnimationDelegate:
+  void AnimationProgressed(const gfx::Animation* animation) override;
+  void AnimationEnded(const gfx::Animation* animation) override;
+
  private:
   friend class test::SliderTestApi;
 
@@ -117,9 +125,6 @@ class VIEWS_EXPORT Slider : public View, public gfx::AnimationDelegate {
   // ui::EventHandler:
   void OnGestureEvent(ui::GestureEvent* event) override;
 
-  // gfx::AnimationDelegate:
-  void AnimationProgressed(const gfx::Animation* animation) override;
-
   void set_listener(SliderListener* listener) {
     listener_ = listener;
   }
@@ -130,7 +135,7 @@ class VIEWS_EXPORT Slider : public View, public gfx::AnimationDelegate {
 
   float value_;
   float keyboard_increment_;
-  float animating_value_;
+  float initial_animating_value_;
   bool value_is_valid_;
   base::string16 accessible_name_;
   bool accessibility_events_enabled_;