Adds initial key systems support for Chromecast.

chromecast/media/base/key_systems_common.cc

Index: chromecast/media/base/key_systems_common.cc
diff --git a/chromecast/media/base/key_systems_common.cc b/chromecast/media/base/key_systems_common.cc
new file mode 100644
index 0000000000000000000000000000000000000000..89257192dbc3d48139ffc008ba0607d60a9a4648
--- /dev/null
+++ b/chromecast/media/base/key_systems_common.cc
@@ -0,0 +1,39 @@
+// 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.
+
+#include "chromecast/media/base/key_systems_common.h"
+
+#include <cstddef>
+
+#include "media/cdm/key_system_names.h"
+
+#include "widevine_cdm_version.h" // In SHARED_INTERMEDIATE_DIR.
+
+namespace chromecast {
+namespace media {
+
+const char kChromecastPlayreadyKeySystem[] = "com.chromecast.playready";
+
+CastKeySystem GetKeySystemByName(const std::string& key_system_name) {
+#if defined(WIDEVINE_CDM_AVAILABLE)
+  if (key_system_name.compare(kWidevineKeySystem) == 0) {
+    return KEY_SYSTEM_WIDEVINE;
+  }
+#endif  // defined(WIDEVINE_CDM_AVAILABLE)
+
+#if defined(PLAYREADY_CDM_AVAILABLE)
+  if (key_system_name.compare(kChromecastPlayreadyKeySystem) == 0) {
+    return KEY_SYSTEM_PLAYREADY;
+  }
+#endif  // defined(PLAYREADY_CDM_AVAILABLE)
+
+  if (key_system_name.compare(::media::kClearKey) == 0) {
+    return KEY_SYSTEM_CLEAR_KEY;
+  }
+
+  return GetPlatformKeySystemByName(key_system_name);
+}
+
+}  // namespace media
+}  // namespace chromecast