Add initial Blink-side support for the Screen Orientation API

Source/modules/screen_orientation/ScreenOrientationClient.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 ScreenOrientationClient_h
+#define ScreenOrientationClient_h
+
+#include "modules/screen_orientation/ScreenOrientation.h"
+
+namespace WebCore {
+
+class ScreenOrientationClient {
+public:
+    virtual ~ScreenOrientationClient() { }
+
+    virtual void lockOrientation(ScreenOrientationValues) = 0;
+    virtual void unlockOrientation() = 0;
+};
+
+} // namespace WebCore
+
+#endif // ScreenOrientationClient_h