Enables hot-tracking for overflow extension buttons in the app menu

ui/views/controls/button/custom_button.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_CONTROLS_BUTTON_CUSTOM_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_CUSTOM_BUTTON_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/events/event_constants.h"
@@ skipping 104 matching lines @@
 
   // Returns true if the event is one that can trigger notifying the listener.
   // This implementation returns true if the left mouse button is down.
   virtual bool IsTriggerableEvent(const ui::Event& event);
 
   // Returns true if the button should become pressed when the user
   // holds the mouse down over the button. For this implementation,
   // we simply return IsTriggerableEvent(event).
   virtual bool ShouldEnterPushedState(const ui::Event& event);
 
+  // Returns true if hover effect should be visible.
+  virtual bool ShouldShowInkDropHover() const;
+
   void set_has_ink_drop_action_on_click(bool has_ink_drop_action_on_click) {
     has_ink_drop_action_on_click_ = has_ink_drop_action_on_click;
   }
 
   // Returns true if the button should enter hovered state; that is, if the
   // mouse is over the button, and no other window has capture (which would
   // prevent the button from receiving MouseExited events and updating its
   // state). This does not take into account enabled state.
   bool ShouldEnterHoveredState();
 
   InkDropDelegate* ink_drop_delegate() const { return ink_drop_delegate_; }
   void set_ink_drop_delegate(InkDropDelegate* ink_drop_delegate) {
     ink_drop_delegate_ = ink_drop_delegate;
   }
 
   // Overridden from View:
   void ViewHierarchyChanged(
       const ViewHierarchyChangedDetails& details) override;
   void OnBlur() override;
 
   // Overridden from Button:
   void NotifyClick(const ui::Event& event) override;
   void OnClickCanceled(const ui::Event& event) override;
 
   const gfx::ThrobAnimation& hover_animation() const {
     return hover_animation_;
   }
 
  private:
-  bool ShouldShowInkDropHover() const;
-
   ButtonState state_;
 
   gfx::ThrobAnimation hover_animation_;
 
   // Should we animate when the state changes? Defaults to true.
   bool animate_on_state_change_;
 
   // Is the hover animation running because StartThrob was invoked?
   bool is_throbbing_;
 
@@ skipping 22 matching lines @@
 
   // The color of the ripple and hover.
   SkColor ink_drop_base_color_;
 
   DISALLOW_COPY_AND_ASSIGN(CustomButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_CUSTOM_BUTTON_H_