Adds public API and loads Cast OSD plane implementation from shared lib

chromecast/public/osd_plane_shlib.h

Index: chromecast/public/osd_plane_shlib.h
diff --git a/chromecast/public/osd_plane_shlib.h b/chromecast/public/osd_plane_shlib.h
new file mode 100644
index 0000000000000000000000000000000000000000..0ee170b019e06f4b0914b0b94d80578beeff6f5a
--- /dev/null
+++ b/chromecast/public/osd_plane_shlib.h
@@ -0,0 +1,25 @@
+// Copyright 2015 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 CHROMECAST_PUBLIC_OSD_PLANE_SHLIB_H_
+#define CHROMECAST_PUBLIC_OSD_PLANE_SHLIB_H_
+
+#include <string>
+#include <vector>
+
+#include "chromecast_export.h"
+
+namespace chromecast {
+
+class OsdPlane;
+
+// Entry point for loading OsdPlane from shared library.
+class CHROMECAST_EXPORT OsdPlaneShlib {
+ public:
+  static OsdPlane* Create(const std::vector<std::string>& argv);
+};
+
+}  // namespace chromecast
+
+#endif  // CHROMECAST_PUBLIC_OSD_PLANE_SHLIB_H_