Oilpan: keep FormData on the heap by default.

Source/modules/fetch/Response.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 "modules/fetch/Response.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/DOMArrayBuffer.h"
@@ skipping 97 matching lines @@
     }
     if (body.isArrayBufferView()) {
         RefPtr<DOMArrayBufferView> arrayBufferView = body.getAsArrayBufferView();
         OwnPtr<BlobData> blobData = BlobData::create();
         blobData->appendBytes(arrayBufferView->baseAddress(), arrayBufferView->byteLength());
         const long long length = blobData->length();
         Blob* blob = Blob::create(BlobDataHandle::create(blobData.release(), length));
         return create(context, blob, ResponseInit(responseInit, exceptionState), exceptionState);
     }
     if (body.isFormData()) {
-        RefPtrWillBeRawPtr<DOMFormData> domFormData = body.getAsFormData();
+        DOMFormData* domFormData = body.getAsFormData();
         OwnPtr<BlobData> blobData = BlobData::create();
         // FIXME: the same code exist in RequestInit::RequestInit().
         RefPtr<FormData> httpBody = domFormData->createMultiPartFormData();
         for (size_t i = 0; i < httpBody->elements().size(); ++i) {
             const FormDataElement& element = httpBody->elements()[i];
             switch (element.m_type) {
             case FormDataElement::data: {
                 blobData->appendBytes(element.m_data.data(), element.m_data.size());
                 break;
             }
@@ skipping 267 matching lines @@
 }
 
 DEFINE_TRACE(Response)
 {
     Body::trace(visitor);
     visitor->trace(m_response);
     visitor->trace(m_headers);
 }
 
 } // namespace blink