[Fetch API] Send request body as a FormData.

Source/modules/fetch/Request.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 Request_h
 #define Request_h
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "bindings/modules/v8/UnionTypesModules.h"
@@ skipping 50 matching lines @@
     const BodyStreamBuffer* bodyBuffer() const override { return m_request->buffer(); }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     Request(ExecutionContext*, FetchRequestData*);
     Request(ExecutionContext*, const WebServiceWorkerRequest&);
     Request(ExecutionContext*, FetchRequestData*, Headers*);
 
     const FetchRequestData* request() const { return m_request; }
-    static Request* createRequestWithRequestOrString(ScriptState*, Request*, const String&, const RequestInit&, ExceptionState&);

[hiroshige, 2015/08/17 08:46:02]

nit optional: I think removing |const| here is to allow
RequestInit::body.release(), but passing non-const reference looks like it is
variable for output.
Using PassOwnPtr<RequestInit> might be clearer.
But it's optional because this is an internal function...

another nit optional: we can remove declaration of 
createRequestWithRequestOrString() here and move
createCopyOfFetchRequestDataForFetch() and createRequestWithRequestOrString()
into an anonymous namespace in Request.cpp.

[yhirano, 2015/08/18 09:12:39]

RequestInit is marked as STACK_ALLOCATED due to an oilpan reason and I would
like to keep it.
The function uses many private methods / members, so I would keep the
declaration.

[hiroshige, 2015/08/18 09:36:53]

Acknowledged.

+    static Request* createRequestWithRequestOrString(ScriptState*, Request*, const String&, RequestInit&, ExceptionState&);
 
     String mimeType() const override;
 
     const Member<FetchRequestData> m_request;
     const Member<Headers> m_headers;
 };
 
 } // namespace blink
 
 #endif // Request_h