Implement Request.context for Fetch API

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 28 matching lines @@
     static Request* create(ExecutionContext*, Request*, const Dictionary&, ExceptionState&);
     static Request* create(ExecutionContext*, FetchRequestData*);
     static Request* create(ExecutionContext*, const WebServiceWorkerRequest&);
 
     const FetchRequestData* request() { return m_request; }
 
     // From Request.idl:
     String method() const;
     KURL url() const;
     Headers* headers() const { return m_headers; }
+    String context() const;
     String referrer() const;
     String mode() const;
     String credentials() const;
 
     // From Request.idl:
     Request* clone(ExceptionState&) const;
 
     FetchRequestData* passRequestData();
 
     void populateWebServiceWorkerRequest(WebServiceWorkerRequest&) const;
@@ skipping 15 matching lines @@
     BodyStreamBuffer* buffer() const override;
     String mimeType() const override;
 
     const Member<FetchRequestData> m_request;
     const Member<Headers> m_headers;
 };
 
 } // namespace blink
 
 #endif // Request_h