Chromecast buildfix: restores AddKeySystemWithCodecs, fixes namespace.

chromecast/renderer/key_systems_cast.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 CHROMECAST_RENDERER_KEY_SYSTEMS_CAST_H_
 #define CHROMECAST_RENDERER_KEY_SYSTEMS_CAST_H_
 
 #include <vector>
 
 #include "media/base/key_system_info.h"
 
 namespace chromecast {
 namespace shell {
 
+// Adds a single key system by name.
+void AddKeySystemWithCodecs(
+    const std::string& key_system_name,
+    std::vector<::media::KeySystemInfo>* concrete_key_systems);
+
 void AddChromecastKeySystems(
     std::vector<::media::KeySystemInfo>* key_systems_info);
 
 // TODO(gunsch): Remove when prefixed EME is removed.
 void AddChromecastPlatformKeySystems(
     std::vector<::media::KeySystemInfo>* key_systems_info);
 
 }  // namespace shell
 }  // namespace chromecast
 
 #endif  // CHROMECAST_RENDERER_KEY_SYSTEMS_CAST_H_