Bug 1101328 - Use AsyncEventDispatcher to dispatch keyschange to MediaKeySession, since it doesn't require an nsIDocument. r=peterv
Bug 1101328 - Rely on CDM to report keys as unusable on when removing sessions. r=jwwang
Bug 1109457 - Hook up CDM session close notification to MediaKeySession. r=jwwang
Bug 1109861 - Add delegate to manage waiting for the CDM to mark key usable. r=kinetik