Added material design mouse hover feedback support.

chrome/browser/ui/views/bar_control_button.h

Index: chrome/browser/ui/views/bar_control_button.h
diff --git a/chrome/browser/ui/views/bar_control_button.h b/chrome/browser/ui/views/bar_control_button.h
index 7a997cc65f6481c165c1193d22e44231e5b93479..34fa9dea3a96ac62bb1bb1bd0b0ab430796b63cf 100644
--- a/chrome/browser/ui/views/bar_control_button.h
+++ b/chrome/browser/ui/views/bar_control_button.h
@@ -37,9 +37,15 @@ class BarControlButton : public views::ImageButton, public views::InkDropHost {
   bool OnMousePressed(const ui::MouseEvent& event) override;
   void OnGestureEvent(ui::GestureEvent* event) override;
   void OnMouseReleased(const ui::MouseEvent& event) override;
+  void OnMouseEntered(const ui::MouseEvent& event) override;
+  void OnMouseExited(const ui::MouseEvent& event) override;
   void NotifyClick(const ui::Event& event) override;
+  void OnEnabledChanged() override;
 
  private:
+  // Updates the |ink_drop_animation_controller_|'s hover state.
+  void UpdateInkDropHoverState();
+
   // views::InkDropHost:
   void AddInkDropLayer(ui::Layer* ink_drop_layer) override;
   void RemoveInkDropLayer(ui::Layer* ink_drop_layer) override;