Adds initial key systems support for Chromecast.

chromecast/media/base/key_systems_common.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_MEDIA_BASE_KEY_SYSTEMS_COMMON_H_

[ddorwin, 2014/09/13 03:27:06]

common? Is this also used in the browser process or something? Is this for IPC
stuff?

[gunsch, 2014/09/15 21:43:38]

Yes. We communicate CDM information over IPC, then do browser-process-side
decryption. (For Chromecast, most of our media playback happens browser-side, in
a fairly-similar-to-Android architecture. xhwang is leading an effort to unify
this).

+#define CHROMECAST_MEDIA_BASE_KEY_SYSTEMS_COMMON_H_
+
+#include <string>
+
+namespace media {

[lcwu1, 2014/09/15 18:09:50]

s/media/chromecast

[gunsch, 2014/09/15 21:43:38]

Done.

+
+extern const char* kPlayreadyKeySystems[];
+extern const char kClearKeySystem[];
+extern const char kUnsupportedClearKeySystem[];
+
+enum CastKeySystem {
+  KEY_SYSTEM_NONE = 0,
+  KEY_SYSTEM_CLEAR_KEY,
+  KEY_SYSTEM_PLAYREADY,

[ddorwin, 2014/09/13 03:27:06]

To avoid confusion, be explicit about CHROMECAST_PLAYREADY. Possibly throughout.

[gunsch, 2014/09/15 21:43:38]

Would prefer to not. This enum is only for use within the chromecast/ directory,
which makes it redundant. Further, we currently respond to requests for various
PlayReady names (added a TODO for the EMEv2 transition) that are all considered
"KEY_SYSTEM_PLAYREADY".

+  KEY_SYSTEM_WIDEVINE
+};
+
+CastKeySystem GetKeySystemByName(const std::string& key_system_name);

[ddorwin, 2014/09/13 03:27:06]

What is the enum used for? I don't see it in this patch.

[gunsch, 2014/09/15 21:43:38]

No, not yet in this patch. This enum is used for our CDM factory (not yet
upstreamed, dependent on xhwang's new CDM code) and for (at the platform level)
switching on how to provide key information to the hardware. It's largely so
that we're not comparing key system name strings everywhere.

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

FYI, such an enum could be generally useful, especially as part of the
unification work. I believe we currently pass strings for Android, which is not
ideal. The AW implementation would need to be made to handle this, though.

[gunsch, 2014/09/16 16:57:59]

Acknowledged.

+
+}  // namespace media
+
+#endif  // CHROMECAST_MEDIA_BASE_KEY_SYSTEMS_COMMON_H_