[Fetch API] Implement Request.formData and Response.formData.

third_party/WebKit/Source/modules/fetch/Response.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 Response_h
 #define Response_h
 
 #include "bindings/core/v8/Dictionary.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/ScriptWrappable.h"
@@ skipping 74 matching lines @@
   // Returns the BodyStreamBuffer of the internal response of |m_response| if
   // any. Otherwise, returns one of |m_response|.
   BodyStreamBuffer* internalBodyBuffer() {
     return m_response->internalBuffer();
   }
   const BodyStreamBuffer* internalBodyBuffer() const {
     return m_response->internalBuffer();
   }
   bool bodyUsed() override;
 
+  String contentType() const override;
   String mimeType() const override;
   String internalMIMEType() const;
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   explicit Response(ExecutionContext*);
   Response(ExecutionContext*, FetchResponseData*);
   Response(ExecutionContext*, FetchResponseData*, Headers*);
 
   void installBody();
   void refreshBody(ScriptState*);
 
   const Member<FetchResponseData> m_response;
   const Member<Headers> m_headers;
 };
 
 }  // namespace blink
 
 #endif  // Response_h