Make IsTriggerableEvent take Event objects and use it to verify whether tap events should trigger.

ui/views/controls/button/button_dropdown.h

 // Copyright (c) 2011 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_BUTTON_DROPDOWN_H_
 #define UI_VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_
 #pragma once
 
 #include "base/memory/weak_ptr.h"
 #include "ui/views/controls/button/image_button.h"
@@ skipping 32 matching lines @@
   // Using the member function ShowDropDownMenu for the actual display.
   virtual void ShowContextMenu(const gfx::Point& p,
                                bool is_mouse_gesture) OVERRIDE;
   virtual void GetAccessibleState(ui::AccessibleViewState* state) OVERRIDE;
 
  protected:
   // Overridden from CustomButton. Returns true if the button should become
   // pressed when a user holds the mouse down over the button. For this
   // implementation, both left and right mouse buttons can trigger a change
   // to the PUSHED state.
-  virtual bool ShouldEnterPushedState(const MouseEvent& event) OVERRIDE;
+  virtual bool ShouldEnterPushedState(const Event& event) OVERRIDE;
 
  private:
   // Internal function to show the dropdown menu
   void ShowDropDownMenu(gfx::NativeView window);
 
   // The model that populates the attached menu.
   ui::MenuModel* model_;
 
   // Y position of mouse when left mouse button is pressed
   int y_position_on_lbuttondown_;
 
   // A factory for tasks that show the dropdown context menu for the button.
   base::WeakPtrFactory<ButtonDropDown> show_menu_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ButtonDropDown);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_BUTTON_DROPDOWN_H_