Make shelf item can be dragged when context menu is opened.

ui/views/controls/menu/submenu_view.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_MENU_SUBMENU_VIEW_H_
 #define UI_VIEWS_CONTROLS_MENU_SUBMENU_VIEW_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 82 matching lines @@
   int GetRowCount() override;
   int GetSelectedRow() override;
   void SetSelectedRow(int row) override;
   base::string16 GetTextForRow(int row) override;
 
   // Returns true if the menu is showing.
   virtual bool IsShowing();
 
   // Shows the menu at the specified location. Coordinates are in screen
   // coordinates. max_width gives the max width the view should be.
-  void ShowAt(Widget* parent, const gfx::Rect& bounds, bool do_capture);
+  void ShowAt(Widget* parent,
+              const gfx::Rect& bounds,
+              bool do_capture,
+              bool cancel_active_touches);
 
   // Resets the bounds of the submenu to |bounds|.
   void Reposition(const gfx::Rect& bounds);
 
   // Closes the menu, destroying the host.
   void Close();
 
   // Hides the hosting window.
   //
   // The hosting window is hidden first, then deleted (Close) when the menu is
@@ skipping 107 matching lines @@
   float roundoff_error_;
 
   PrefixSelector prefix_selector_;
 
   DISALLOW_COPY_AND_ASSIGN(SubmenuView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_MENU_SUBMENU_VIEW_H_