[ServiceWorker] Implement Headers class.

Source/modules/serviceworkers/HeadersForEachCallback.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 HeaderMapForEachCallback_h
-#define HeaderMapForEachCallback_h
+#ifndef HeadersForEachCallback_h
+#define HeadersForEachCallback_h
 
 #include "bindings/v8/ScriptValue.h"
 
 namespace WebCore {
 
-class HeaderMap;
+class Headers;
 
-class HeaderMapForEachCallback {
+class HeadersForEachCallback {
 public:
-    virtual ~HeaderMapForEachCallback() { }
-    virtual bool handleItem(ScriptValue thisValue, const String& value, const String& key, HeaderMap*) = 0;
-    virtual bool handleItem(const String& value, const String& key, HeaderMap*) = 0;
+    virtual ~HeadersForEachCallback() { }
+    virtual bool handleItem(ScriptValue thisValue, const String& value, const String& key, Headers*) = 0;
+    virtual bool handleItem(const String& value, const String& key, Headers*) = 0;
 };
 
 } // namespace WebCore
 
-#endif // HeaderMapForEachCallback_h
+#endif // HeadersForEachCallback_h