Implement the infrastructure of creating WorkerFetchContext in worker global scope.

third_party/WebKit/Source/core/loader/FrameFetchContext.h

 /*
  * Copyright (C) 2013 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 53 matching lines @@
   static void ProvideDocumentToContext(FetchContext& context,
                                        Document* document) {
     DCHECK(document);
     CHECK(context.IsLiveContext());
     static_cast<FrameFetchContext&>(context).document_ = document;
   }
 
   ~FrameFetchContext();
 
   bool IsLiveContext() { return true; }
+  WebURLLoader* CreateURLLoader() override;
 
   void AddAdditionalRequestHeaders(ResourceRequest&,
                                    FetchResourceType) override;
   WebCachePolicy ResourceRequestCachePolicy(
       ResourceRequest&,
       Resource::Type,
       FetchParameters::DeferOption) const override;
   void DispatchDidChangeResourcePriority(unsigned long identifier,
                                          ResourceLoadPriority,
                                          int intra_priority_value) override;
@@ skipping 116 matching lines @@
   // FIXME: Oilpan: Ideally this should just be a traced Member but that will
   // currently leak because ComputedStyle and its data are not on the heap.
   // See crbug.com/383860 for details.
   WeakMember<Document> document_;
   Member<DocumentLoader> document_loader_;
 };
 
 }  // namespace blink
 
 #endif