Add MD ink drop ripple to app list button

ash/shelf/app_list_button.h

Index: ash/shelf/app_list_button.h
diff --git a/ash/shelf/app_list_button.h b/ash/shelf/app_list_button.h
index df3d2a1eb310cf8ad5edd3ea5d44308e13ab4bf3..077460ea704dfa641f30f5289e3e3642ab5525d9 100644
--- a/ash/shelf/app_list_button.h
+++ b/ash/shelf/app_list_button.h
@@ -19,6 +19,9 @@ class AppListButton : public views::ImageButton {
                          ShelfView* shelf_view);
   ~AppListButton() override;
 
+  void OnAppListShown();
+  void OnAppListDismissed();
+
   bool draw_background_as_active() { return draw_background_as_active_; }
 
  protected:
@@ -29,7 +32,10 @@ class AppListButton : public views::ImageButton {
   bool OnMouseDragged(const ui::MouseEvent& event) override;
   void OnPaint(gfx::Canvas* canvas) override;
   void GetAccessibleState(ui::AXViewState* state) override;
+  std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override;
   void NotifyClick(const ui::Event& event) override;
+  bool ShouldEnterPushedState(const ui::Event& event) override;
+  bool ShouldShowInkDropHighlight() const override;
 
   // ui::EventHandler overrides:
   void OnGestureEvent(ui::GestureEvent* event) override;