[ash-md] Added different highlighting modes to the InkDropImpl.

ash/common/shelf/shelf_button.h

Index: ash/common/shelf/shelf_button.h
diff --git a/ash/common/shelf/shelf_button.h b/ash/common/shelf/shelf_button.h
index 243bbad01df0224e350b15fbd804c6463cd563fc..962185f0eb10952e6ea20ee5a8020c3b82a58004 100644
--- a/ash/common/shelf/shelf_button.h
+++ b/ash/common/shelf/shelf_button.h
@@ -11,6 +11,10 @@
 #include "ui/views/controls/button/custom_button.h"
 #include "ui/views/controls/image_view.h"
 
+namespace views {
+class InkDrop;
+}  // namespace views
+
 namespace ash {
 class InkDropButtonListener;
 class ShelfView;
@@ -84,7 +88,7 @@ class ASH_EXPORT ShelfButton : public views::CustomButton {
   // views::CustomButton overrides:
   std::unique_ptr<views::InkDropRipple> CreateInkDropRipple() const override;
   bool ShouldEnterPushedState(const ui::Event& event) override;
-  bool ShouldShowInkDropHighlight() const override;
+  std::unique_ptr<views::InkDrop> CreateInkDrop() override;
   void NotifyClick(const ui::Event& event) override;
 
   // Sets the icon image with a shadow.