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 713cdeaa80a44297c604e2b94dc4264fade7cc59..0b1acf0823d9d4e8a79018b721cd8a304cfa51ed 100644
--- a/ui/views/controls/button/custom_button.h
+++ b/ui/views/controls/button/custom_button.h
@@ -8,6 +8,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/event_constants.h"
 #include "ui/gfx/animation/animation_delegate.h"
+#include "ui/views/animation/ink_drop_consumer.h"
 #include "ui/views/controls/button/button.h"
 
 namespace gfx {
@@ -21,7 +22,8 @@ namespace views {
 // part of the focus chain.  Call SetFocusable(true) to make it part of the
 // focus chain.
 class VIEWS_EXPORT CustomButton : public Button,
-                                  public gfx::AnimationDelegate {
+                                  public gfx::AnimationDelegate,
+                                  public views::InkDropConsumer {
  public:
   // An enum describing the events on which a button should notify its listener.
   enum NotifyAction {
@@ -98,6 +100,9 @@ class VIEWS_EXPORT CustomButton : public Button,
   // Overridden from gfx::AnimationDelegate:
   void AnimationProgressed(const gfx::Animation* animation) override;
 
+  // Overriden from views::InkDropConsumer:
+  bool ShouldShowInkDropHover() override;
+
  protected:
   // Construct the Button with a Listener. See comment for Button's ctor.
   explicit CustomButton(ButtonListener* listener);