Remove resource type-specific fetching logic from ResourceFetcher

Source/core/fetch/CSSStyleSheetResource.h

Index: Source/core/fetch/CSSStyleSheetResource.h
diff --git a/Source/core/fetch/CSSStyleSheetResource.h b/Source/core/fetch/CSSStyleSheetResource.h
index 2ce492d91b21c12b6e0d269016d8ff3ff027d153..ed2d628419028a7b181f2f3617a525eb42fea5b1 100644
--- a/Source/core/fetch/CSSStyleSheetResource.h
+++ b/Source/core/fetch/CSSStyleSheetResource.h
@@ -33,12 +33,15 @@
 namespace blink {
 
 class CSSParserContext;
+class FetchRequest;
 class ResourceClient;
+class ResourceFetcher;
 class StyleSheetContents;
 
 class CSSStyleSheetResource final : public StyleSheetResource {
 public:
-    CSSStyleSheetResource(const ResourceRequest&, const String& charset);
+    static ResourcePtr<CSSStyleSheetResource> fetch(FetchRequest&, ResourceFetcher*);
+
     virtual ~CSSStyleSheetResource();
     DECLARE_VIRTUAL_TRACE();
 
@@ -56,6 +59,18 @@ protected:
     virtual void destroyDecodedDataIfPossible() override;
 
 private:
+    class CSSStyleSheetResourceFactory : public ResourceFactory {
+    public:
+        CSSStyleSheetResourceFactory()
+            : ResourceFactory(Resource::CSSStyleSheet) { }
+
+        Resource* create(const ResourceRequest& request, const String& charset) const override
+        {
+            return new CSSStyleSheetResource(request, charset);
+        }
+    };
+    CSSStyleSheetResource(const ResourceRequest&, const String& charset);
+
     bool canUseSheet(bool* hasValidMIMEType) const;
     virtual void dispose() override;
     virtual void checkNotify() override;