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..da191865d0e33a71767546bf2a8cb53652323f50
--- /dev/null
+++ b/chromecast/media/base/key_systems_common.cc
@@ -0,0 +1,50 @@
+// 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 {
+
+// TODO(gunsch): remove this support when moving to EMEv2.

[ddorwin, 2014/09/15 22:50:53]

The correct term is "unprefixed EME". It's not really "v2".

[gunsch, 2014/09/16 16:58:00]

Done.

+// See also: crbug/393397

[ddorwin, 2014/09/15 22:50:53]

I don't think this bug addresses the clear key naming issue.

[gunsch, 2014/09/16 16:58:00]

Done.

+const char kUnsupportedClearKeySystem[] = "unsupported-org.w3.clearkey";
+
+const char* kPlayreadyKeySystems[] = {
+  // TODO(gunsch): Replace with a more appropriate name when moving to EMEv2.
+  // See also: crbug/393397.
+  "com.microsoft.playready",
+  "com.youtube.playready",
+  NULL,
+};
+
+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)
+  for (size_t i = 0; kPlayreadyKeySystems[i] != NULL; i++) {
+    if (key_system_name.compare(kPlayreadyKeySystems[i]) == 0) {
+      return KEY_SYSTEM_PLAYREADY;
+    }
+  }
+#endif  // defined(PLAYREADY_CDM_AVAILABLE)
+
+  if (key_system_name.compare(::media::kClearKey) == 0 ||
+      key_system_name.compare(kUnsupportedClearKeySystem) == 0) {
+    return KEY_SYSTEM_CLEAR_KEY;
+  }
+
+  return KEY_SYSTEM_NONE;
+}
+
+}  // namespace chromecast