[ServiceWorker] Use BodyStreamBuffer as the body data of the Response object.

Source/modules/serviceworkers/FetchRequestData.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 "FetchRequestData.h"
 
 #include "core/dom/ExecutionContext.h"
 #include "core/fetch/ResourceLoaderOptions.h"
 #include "core/loader/ThreadableLoader.h"
@@ skipping 50 matching lines @@
     , m_headerList(FetchHeaderList::create())
     , m_unsafeRequestFlag(false)
     , m_context(WebURLRequest::RequestContextUnspecified)
     , m_sameOriginDataURLFlag(false)
     , m_mode(WebURLRequest::FetchRequestModeNoCORS)
     , m_credentials(WebURLRequest::FetchCredentialsModeOmit)
     , m_responseTainting(BasicTainting)
 {
 }
 
+String FetchRequestData::contentType() const

[yhirano, 2014/12/12 12:42:33]

Is this function's meaning clear?
This function is called only in Body, when m_blobDataHandle is null. It means
that this function always return an empty string and that seems wrong.

[horo, 2014/12/15 02:12:24]

Removed and I introduced contentTypeForBuffer to Body.

+{
+    if (m_blobDataHandle)
+        return m_blobDataHandle->type();
+    return "";

[yhirano, 2014/12/12 12:42:32]

return String() is more efficient.

[horo, 2014/12/15 02:12:24]

Done in Request::contentTypeForBuffer().

+}
+
 void FetchRequestData::trace(Visitor* visitor)
 {
     visitor->trace(m_headerList);
 }
 
 } // namespace blink