Cleanup: Add more conversion helpers for usage.

Source/web/WebSharedWorkerImpl.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 130 matching lines @@
     webFrame->frame()->loader()->load(FrameLoadRequest(0, ResourceRequest(url), SubstituteData(buffer, "text/html", "UTF-8", KURL())));
 
     // This document will be used as 'loading context' for the worker.
     m_loadingDocument = webFrame->frame()->document();
 }
 
 void WebSharedWorkerImpl::didCreateDataSource(WebFrame*, WebDataSource* ds)
 {
     // Tell the loader to load the data into the 'shadow page' synchronously,
     // so we can grab the resulting Document right after load.
-    static_cast<WebDataSourceImpl*>(ds)->setDeferMainResourceDataLoad(false);
+    toWebDataSourceImpl(ds)->setDeferMainResourceDataLoad(false);
 }
 
 WebApplicationCacheHost* WebSharedWorkerImpl::createApplicationCacheHost(WebFrame*, WebApplicationCacheHostClient* appcacheHostClient)
 {
     if (client())
         return client()->createApplicationCacheHost(appcacheHostClient);
     return 0;
 }
 
 // WorkerObjectProxy -----------------------------------------------------------
@@ skipping 280 matching lines @@
     workerThread()->runLoop().postTaskForMode(createCallbackTask(dispatchOnInspectorBackendTask, String(message)), WorkerDebuggerAgent::debuggerTaskMode);
     WorkerDebuggerAgent::interruptAndDispatchInspectorCommands(workerThread());
 }
 
 WebSharedWorker* WebSharedWorker::create(WebSharedWorkerClient* client)
 {
     return new WebSharedWorkerImpl(client);
 }
 
 } // namespace WebKit