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 ee898afb5b58ea1d17c8b381df699c938f43d2e4..d4c16d0b6fb3d1516b689e6f4d7cb382069d5009 100644
--- a/Source/core/fetch/CSSStyleSheetResource.h
+++ b/Source/core/fetch/CSSStyleSheetResource.h
@@ -33,14 +33,17 @@
 namespace blink {
 
 class CSSParserContext;
+class FetchRequest;
 class ResourceClient;
+class ResourceFetcher;
 class StyleSheetContents;
 
 class CSSStyleSheetResource final : public StyleSheetResource {
 public:
     enum class MIMETypeCheck { Strict, Lax };
 
-    CSSStyleSheetResource(const ResourceRequest&, const String& charset);
+    static ResourcePtr<CSSStyleSheetResource> fetch(FetchRequest&, ResourceFetcher*);
+
     virtual ~CSSStyleSheetResource();
     DECLARE_VIRTUAL_TRACE();
 
@@ -58,6 +61,18 @@ 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(MIMETypeCheck) const;
     virtual void dispose() override;
     virtual void checkNotify() override;