Added material design mouse hover feedback support.

ui/views/controls/button/custom_button.h

Index: ui/views/controls/button/custom_button.h
diff --git a/ui/views/controls/button/custom_button.h b/ui/views/controls/button/custom_button.h
index 6d23e8e08affb3a9644a17a74c5b80a4b3f8d2fd..7f394087715d52d6162846fafb264da4ec68ae6b 100644
--- a/ui/views/controls/button/custom_button.h
+++ b/ui/views/controls/button/custom_button.h
@@ -106,6 +106,7 @@ class VIEWS_EXPORT CustomButton : public Button,
   void AddInkDropLayer(ui::Layer* ink_drop_layer) override;
   void RemoveInkDropLayer(ui::Layer* ink_drop_layer) override;
   gfx::Point CalculateInkDropCenter() const override;
+  bool ShouldShowInkDropHover() const override;
 
  protected:
   // Construct the Button with a Listener. See comment for Button's ctor.
@@ -136,6 +137,9 @@ class VIEWS_EXPORT CustomButton : public Button,
   // state). This does not take into account enabled state.
   bool ShouldEnterHoveredState();
 
+  // Updates the |ink_drop_delegate_|'s hover state.
+  void UpdateInkDropHoverState();
+
   InkDropDelegate* ink_drop_delegate() const { return ink_drop_delegate_; }
   void set_ink_drop_delegate(InkDropDelegate* ink_drop_delegate) {
     ink_drop_delegate_ = ink_drop_delegate;