Cleanup: Add more conversion helpers for usage.

Source/web/WebFrameImpl.cpp

 /*
  * Copyright (C) 2009 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 2237 matching lines @@
         webView->suppressInvalidations(false);
 
     if (isMainFrame && webView->devToolsAgentPrivate())
         webView->devToolsAgentPrivate()->mainFrameViewCreated(this);
 }
 
 WebFrameImpl* WebFrameImpl::fromFrame(Frame* frame)
 {
     if (!frame)
         return 0;
-    return static_cast<FrameLoaderClientImpl*>(frame->loader()->client())->webFrame();
+    return toFrameLoaderClientImpl(frame->loader()->client())->webFrame();
 }
 
 WebFrameImpl* WebFrameImpl::fromFrameOwnerElement(Element* element)
 {
     // FIXME: Why do we check specifically for <iframe> and <frame> here? Why can't we get the WebFrameImpl from an <object> element, for example.
     if (!element || !element->isFrameOwnerElement() || (!element->hasTagName(HTMLNames::iframeTag) && !element->hasTagName(HTMLNames::frameTag)))
         return 0;
     return fromFrame(toHTMLFrameOwnerElement(element)->contentFrame());
 }
 
 WebViewImpl* WebFrameImpl::viewImpl() const
 {
     if (!frame())
         return 0;
     return WebViewImpl::fromPage(frame()->page());
 }
 
 WebDataSourceImpl* WebFrameImpl::dataSourceImpl() const
 {
-    return static_cast<WebDataSourceImpl*>(dataSource());
+    return toWebDataSourceImpl(dataSource());
 }
 
 WebDataSourceImpl* WebFrameImpl::provisionalDataSourceImpl() const
 {
-    return static_cast<WebDataSourceImpl*>(provisionalDataSource());
+    return toWebDataSourceImpl(provisionalDataSource());
 }
 
 void WebFrameImpl::setFindEndstateFocusAndSelection()
 {
     WebFrameImpl* mainFrameImpl = viewImpl()->mainFrameImpl();
 
     if (this == mainFrameImpl->activeMatchFrame() && m_activeMatch.get()) {
         // If the user has set the selection since the match was found, we
         // don't focus anything.
         VisibleSelection selection(frame()->selection().selection());
@@ skipping 220 matching lines @@
 
         // There is a possibility that the frame being detached was the only
         // pending one. We need to make sure final replies can be sent.
         flushCurrentScopingEffort(m_findRequestIdentifier);
 
         cancelPendingScopingEffort();
     }
 }
 
 } // namespace WebKit