Refactoring: Add convenience method toPluginContainerImpl.

Source/web/ContextMenuClientImpl.cpp

 /*
  * Copyright (C) 2009, 2012 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 232 matching lines @@
             data.mediaFlags |= WebContextMenuData::MediaHasVideo;
         if (mediaElement->controls())
             data.mediaFlags |= WebContextMenuData::MediaControls;
     } else if (r.innerNonSharedNode()->hasTagName(HTMLNames::objectTag)
                || r.innerNonSharedNode()->hasTagName(HTMLNames::embedTag)) {
         RenderObject* object = r.innerNonSharedNode()->renderer();
         if (object && object->isWidget()) {
             Widget* widget = toRenderWidget(object)->widget();
             if (widget && widget->isPluginContainer()) {
                 data.mediaType = WebContextMenuData::MediaTypePlugin;
-                WebPluginContainerImpl* plugin = static_cast<WebPluginContainerImpl*>(widget);
+                WebPluginContainerImpl* plugin = toPluginContainerImpl(widget);
                 WebString text = plugin->plugin()->selectionAsText();
                 if (!text.isEmpty()) {
                     data.selectedText = text;
                     data.editFlags |= WebContextMenuData::CanCopy;
                 }
                 data.editFlags &= ~WebContextMenuData::CanTranslate;
                 data.linkURL = plugin->plugin()->linkAtPosition(data.mousePosition);
                 if (plugin->plugin()->supportsPaginatedPrint())
                     data.mediaFlags |= WebContextMenuData::MediaCanPrint;
 
@@ skipping 148 matching lines @@
         outputItems[i] = subItems[i];
     subMenuItems.swap(outputItems);
 }
 
 void ContextMenuClientImpl::populateCustomMenuItems(const WebCore::ContextMenu* defaultMenu, WebContextMenuData* data)
 {
     populateSubMenuItems(defaultMenu->items(), data->customItems);
 }
 
 } // namespace WebKit