Add initial home card impl.

athena/home/public/home_card.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 ATHENA_HOME_PUBLIC_HOME_CARD_H_
+#define ATHENA_HOME_PUBLIC_HOME_CARD_H_
+
+#include "athena/athena_export.h"
+
+namespace athena {
+
+class ATHENA_EXPORT HomeCard {
+ public:
+  // Creates and deletes the singleton object of the HomeCard
+  // implementation.
+  static HomeCard* Create();
+  static void Shutdown();
+
+  virtual ~HomeCard() {}
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_HOME_PUBLIC_HOME_CARD_H_