Revert of [ServiceWorker] Make Response class better conformance with the spec.

Source/modules/serviceworkers/HeaderMapForEachCallback.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
+
+#include "bindings/core/v8/ScriptValue.h"
+
+namespace WebCore {
+
+class HeaderMap;
+
+class HeaderMapForEachCallback {
+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;
+};
+
+} // namespace WebCore
+
+#endif // HeaderMapForEachCallback_h