Add Frame and RemoteFrame classes.

Source/core/frame/RemoteFrame.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 RemoteFrame_h
+#define RemoteFrame_h
+
+#include "core/frame/Frame.h"
+
+namespace WebCore {
+
+class RemoteFrame: public Frame {
+public:
+    static PassRefPtr<RemoteFrame> create(PassRefPtr<FrameInit>);
+    virtual bool isRemoteFrame() const OVERRIDE { return true; }
+
+    virtual ~RemoteFrame();
+
+private:
+    RemoteFrame(PassRefPtr<FrameInit>);
+};
+
+DEFINE_TYPE_CASTS(RemoteFrame, Frame, remoteFrame, remoteFrame->isRemoteFrame(), remoteFrame.isRemoteFrame());
+
+} // namespace WebCore
+
+#endif // RemoteFrame_h