ServiceWorker: Fix conversion from Request headers to WebServiceWorkerRequest headers

Source/modules/serviceworkers/Request.cpp

 // 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.
 
 #include "config.h"
 #include "Request.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/fetch/FetchUtils.h"
@@ skipping 18 matching lines @@
     FillWebRequestHeaders(WebServiceWorkerRequest* webRequest) : m_webRequest(webRequest) { }
 
     virtual bool handleItem(ScriptValue, const String&, const String&, Headers*)
     {
         ASSERT_NOT_REACHED();
         return false;
     }
 
     virtual bool handleItem(const String& value, const String& key, Headers*)
     {
-        m_webRequest->setHeader(key, value);
+        m_webRequest->appendHeader(key, value);
         return true;
     }
 
 private:
     WebServiceWorkerRequest* m_webRequest;
 };
 
 Request* createRequestWithRequestData(ExecutionContext* context, FetchRequestData* request, const RequestInit& init, FetchRequestData::Mode mode, FetchRequestData::Credentials credentials, ExceptionState& exceptionState)
 {
     // "7. Let |mode| be |init|'s mode member if it is present, and
@@ skipping 275 matching lines @@
 }
 
 void Request::trace(Visitor* visitor)
 {
     Body::trace(visitor);
     visitor->trace(m_request);
     visitor->trace(m_headers);
 }
 
 } // namespace blink