Service Workers/Fetch: Fix Response constructor for empty/null

Source/modules/serviceworkers/Response.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef Response_h
 #define Response_h
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "modules/serviceworkers/Body.h"
 #include "modules/serviceworkers/FetchResponseData.h"
 #include "modules/serviceworkers/Headers.h"
 #include "platform/blob/BlobData.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class Blob;
 class DOMArrayBuffer;
 class DOMArrayBufferView;
 class ExceptionState;
 class ResponseInit;
 class WebServiceWorkerResponse;
 
 class Response final : public Body {
     DEFINE_WRAPPERTYPEINFO();
 public:
     virtual ~Response() { }
+    // Constructors from Response.idl:
+    static Response* create(ExecutionContext*, ExceptionState&);
     static Response* create(ExecutionContext*, Blob*, const Dictionary&, ExceptionState&);
     static Response* create(ExecutionContext*, const String&, const Dictionary&, ExceptionState&);
     static Response* create(ExecutionContext*, const DOMArrayBuffer*, const Dictionary&, ExceptionState&);
     static Response* create(ExecutionContext*, const DOMArrayBufferView*, const Dictionary&, ExceptionState&);
+
     static Response* create(ExecutionContext*, Blob*, const ResponseInit&, ExceptionState&);
     static Response* create(ExecutionContext*, FetchResponseData*);
     static Response* create(ExecutionContext*, const WebServiceWorkerResponse&);
     // The 'FetchResponseData' object is shared between responses, as it is
     // immutable to the user after Response creation. Headers are copied.
     static Response* create(const Response&);
 
     const FetchResponseData* response() const { return m_response; }
 
+    // From Response.idl:
     String type() const;
     String url() const;
     unsigned short status() const;
     String statusText() const;
     Headers* headers() const;
 
+    // From Response.idl:
     Response* clone() const;
 
     void populateWebServiceWorkerResponse(WebServiceWorkerResponse&);
 
     virtual void trace(Visitor*) override;
 
 private:
     explicit Response(const Response&);
     explicit Response(ExecutionContext*);
     Response(ExecutionContext*, FetchResponseData*);
 
     virtual PassRefPtr<BlobDataHandle> blobDataHandle() override;
 
     const Member<FetchResponseData> m_response;
     const Member<Headers> m_headers;
 };
 
 } // namespace blink
 
 #endif // Response_h