Move Fetch API releted code to modules/fetch.

Source/modules/fetch/Headers.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 Headers_h
 #define Headers_h
 
 #include "bindings/core/v8/ScriptState.h"
 #include "bindings/core/v8/ScriptWrappable.h"
-#include "modules/serviceworkers/FetchHeaderList.h"
+#include "modules/fetch/FetchHeaderList.h"
 #include "wtf/Forward.h"
 #include "wtf/PassOwnPtr.h"
 
 namespace blink {
 
 class Dictionary;
 class ExceptionState;
 class Iterator;
 
 // http://fetch.spec.whatwg.org/#headers-class
@@ skipping 40 matching lines @@
     // Shares the FetchHeaderList. Called when creating a Request or Response.
     explicit Headers(FetchHeaderList*);
 
     Member<FetchHeaderList> m_headerList;
     Guard m_guard;
 };
 
 } // namespace blink
 
 #endif // Headers_h