Remove dead ContextMenu code from Blink core

Source/core/platform/ContextMenu.cpp

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/platform/ContextMenu.h"
 
 namespace WebCore {
 
-ContextMenu::ContextMenu()
-{
-}
-
 static const ContextMenuItem* findItemWithAction(unsigned action, const Vector<ContextMenuItem>& items)
 {
     for (size_t i = 0; i < items.size(); ++i) {
         const ContextMenuItem& item = items[i];
         if (item.action() == static_cast<ContextMenuAction>(action))
             return &item;
         if (item.type() != SubmenuType)
             continue;
         if (const ContextMenuItem* subMenuItem = findItemWithAction(action, item.subMenuItems()))
             return subMenuItem;
     }
 
     return 0;
 }
 
-const ContextMenuItem* ContextMenu::itemWithAction(unsigned action)
+const ContextMenuItem* ContextMenu::itemWithAction(unsigned action) const
 {
     return findItemWithAction(action, m_items);
 }
 
 } // namespace WebCore