Fix conversion to WebServiceWorkerResponse headers.

Source/modules/serviceworkers/FetchResponseData.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 "FetchResponseData.h"
 
 #include "core/fetch/CrossOriginAccessControl.h"
 #include "modules/serviceworkers/FetchHeaderList.h"
 #include "public/platform/WebServiceWorkerResponse.h"
@@ skipping 73 matching lines @@
 {
     if (m_internalResponse) {
         m_internalResponse->populateWebServiceWorkerResponse(response);
         return;
     }
     response.setURL(url());
     response.setStatus(status());
     response.setStatusText(statusMessage());
     for (size_t i = 0; i < headerList()->size(); ++i) {
         const FetchHeaderList::Header* header = headerList()->list()[i].get();
-        response.setHeader(header->first, header->second);
+        response.appendHeader(header->first, header->second);
     }
     response.setBlobDataHandle(blobDataHandle());
 }
 
 FetchResponseData::FetchResponseData(Type type, unsigned short status, AtomicString statusMessage)
     : m_type(type)
     , m_status(status)
     , m_statusMessage(statusMessage)
     , m_headerList(FetchHeaderList::create())
 {
 }
 
 void FetchResponseData::trace(Visitor* visitor)
 {
     visitor->trace(m_headerList);
     visitor->trace(m_internalResponse);
 }
 
 } // namespace blink