Implement MediaValues for initial viewport.

third_party/WebKit/Source/core/css/MediaValuesInitialViewport.h

+// Copyright 2016 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 MediaValuesInitialViewport_h
+#define MediaValuesInitialViewport_h
+
+#include "core/css/MediaValuesDynamic.h"
+
+namespace blink {
+
+class CORE_EXPORT MediaValuesInitialViewport final : public MediaValuesDynamic {
+ public:
+  static MediaValues* create(LocalFrame&);
+
+  double viewportWidth() const override;
+  double viewportHeight() const override;
+
+ private:
+  MediaValuesInitialViewport(LocalFrame&);
+};
+
+}  // namespace blink
+
+#endif  // MediaValuesInitialViewport_h