Remove resource type-specific fetching logic from ResourceFetcher

Source/core/loader/ImageLoader.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 289 matching lines @@
 
         // Prevent the immediate creation of a ResourceLoader (and therefore a network
         // request) for ImageDocument loads. In this case, the image contents have already
         // been requested as a main resource and ImageDocumentParser will take care of
         // funneling the main resource bytes into the ImageResource.
         if (m_loadingImageDocument) {
             request.setDefer(FetchRequest::DeferredByClient);
             request.setContentSecurityCheck(DoNotCheckContentSecurityPolicy);
         }
 
-        newImage = document.fetcher()->fetchImage(request);
+        newImage = ImageResource::fetch(request, document.fetcher());
         if (m_loadingImageDocument && newImage)
             newImage->setLoading(true);
 
         if (!newImage && !pageIsBeingDismissed(&document)) {
             crossSiteOrCSPViolationOccurred(imageSourceURL);
             dispatchErrorEvent();
         } else {
             clearFailedLoadURL();
         }
     } else {
@@ skipping 339 matching lines @@
 #endif
 }
 
 #if ENABLE(OILPAN)
 ImageLoader::ImageLoaderClientRemover::~ImageLoaderClientRemover()
 {
     m_loader.willRemoveClient(m_client);
 }
 #endif
 }