Adding ripple effect for clicks on MD slider

ui/views/controls/slider.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_VIEWS_CONTROLS_SLIDER_H_
 #define UI_VIEWS_CONTROLS_SLIDER_H_
 
 #include "base/macros.h"
 #include "ui/gfx/animation/animation_delegate.h"
 #include "ui/views/view.h"
@@ skipping 54 matching lines @@
   void set_enable_accessibility_events(bool enabled) {
     accessibility_events_enabled_ = enabled;
   }
 
   void set_focus_border_color(SkColor color) { focus_border_color_ = color; }
 
   // Update UI based on control on/off state.
   virtual void UpdateState(bool control_on) = 0;
 
  protected:
+  bool OnMousePressed(const ui::MouseEvent& event) override;
+  void OnMouseReleased(const ui::MouseEvent& event) override;
+
+ protected:
   explicit Slider(SliderListener* listener);
 
   // Returns the current position of the thumb on the slider.
   float GetAnimatingValue() const;
 
   virtual int GetThumbWidth() = 0;
 
   // views::View:
   void OnPaint(gfx::Canvas* canvas) override;
 
@@ skipping 14 matching lines @@
 
   // Notify the listener_, if not NULL, that dragging started.
   void OnSliderDragStarted();
 
   // Notify the listener_, if not NULL, that dragging ended.
   void OnSliderDragEnded();
 
   // views::View:
   const char* GetClassName() const override;
   gfx::Size GetPreferredSize() const override;
-  bool OnMousePressed(const ui::MouseEvent& event) override;
   bool OnMouseDragged(const ui::MouseEvent& event) override;
-  void OnMouseReleased(const ui::MouseEvent& event) override;
   bool OnKeyPressed(const ui::KeyEvent& event) override;
   void GetAccessibleState(ui::AXViewState* state) override;
   void OnFocus() override;
   void OnBlur() override;
 
   // ui::EventHandler:
   void OnGestureEvent(ui::GestureEvent* event) override;
 
   // gfx::AnimationDelegate:
   void AnimationProgressed(const gfx::Animation* animation) override;
@@ skipping 17 matching lines @@
   // Relative position of the mouse cursor (or the touch point) on the slider's
   // button.
   int initial_button_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(Slider);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_SLIDER_H_