Remove resource type-specific fetching logic from ResourceFetcher

Source/core/fetch/DocumentResource.h

 /*
     Copyright (C) 2010 Rob Buis <rwlbuis@gmail.com>
     Copyright (C) 2011 Cosmin Truta <ctruta@gmail.com>
     Copyright (C) 2012 University of Szeged
     Copyright (C) 2012 Renata Hodovan <reni@webkit.org>
 
     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 13 matching lines @@
 #define DocumentResource_h
 
 #include "core/fetch/Resource.h"
 #include "core/fetch/ResourceClient.h"
 #include "core/fetch/ResourcePtr.h"
 #include "core/html/parser/TextResourceDecoder.h"
 
 namespace blink {
 
 class Document;
+class FetchRequest;
+class ResourceFetcher;
 
 class DocumentResource final : public Resource {
 public:
     typedef ResourceClient ClientType;
 
-    DocumentResource(const ResourceRequest&, Type);
+    static ResourcePtr<DocumentResource> fetchSVGDocument(FetchRequest&, ResourceFetcher*);
     virtual ~DocumentResource();
     DECLARE_VIRTUAL_TRACE();
 
     Document* document() const { return m_document.get(); }
 
     virtual void setEncoding(const String&) override;
     virtual String encoding() const override;
     virtual void checkNotify() override;
 
 private:
+    class SVGDocumentResourceFactory : public ResourceFactory {
+    public:
+        SVGDocumentResourceFactory()
+            : ResourceFactory(Resource::SVGDocument) { }
+
+        Resource* create(const ResourceRequest& request, const String& charset) const override
+        {
+            return new DocumentResource(request, Resource::SVGDocument);
+        }
+    };
+    DocumentResource(const ResourceRequest&, Type);
+
     PassRefPtrWillBeRawPtr<Document> createDocument(const KURL&);
 
     RefPtrWillBeMember<Document> m_document;
     OwnPtr<TextResourceDecoder> m_decoder;
 };
 
 DEFINE_TYPE_CASTS(DocumentResource, Resource, resource, resource->type() == Resource::SVGDocument, resource.type() == Resource::SVGDocument); \
 inline DocumentResource* toDocumentResource(const ResourcePtr<Resource>& ptr) { return toDocumentResource(ptr.get()); }
 
 class DocumentResourceClient : public ResourceClient {
 public:
     virtual ~DocumentResourceClient() { }
     static ResourceClientType expectedType() { return DocumentType; }
     virtual ResourceClientType resourceClientType() const override { return expectedType(); }
 };
 
 }
 
 #endif // DocumentResource_h