Cast: Added support for AES-CTR crypto.

media/cast/audio_receiver/audio_receiver.h

Index: media/cast/audio_receiver/audio_receiver.h
diff --git a/media/cast/audio_receiver/audio_receiver.h b/media/cast/audio_receiver/audio_receiver.h
index 2044e16cfc81d20f418767529f72ce3a7c2e349b..313025bc50d9602e8cf8617d45aed70cfae97e5d 100644
--- a/media/cast/audio_receiver/audio_receiver.h
+++ b/media/cast/audio_receiver/audio_receiver.h
@@ -13,6 +13,7 @@
 #include "base/threading/non_thread_safe.h"
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
+#include "crypto/encryptor.h"
 #include "media/cast/cast_config.h"
 #include "media/cast/cast_environment.h"
 #include "media/cast/cast_receiver.h"
@@ -81,6 +82,9 @@ class AudioReceiver : public base::NonThreadSafe,
   // Return the playout time based on the current time and rtp timestamp.
   base::TimeTicks GetPlayoutTime(base::TimeTicks now, uint32 rtp_timestamp);
 
+  bool DecryptAudioFrame(const EncodedAudioFrame* encrypted_frame,

[Alpha Left Google, 2013/11/07 01:10:11]

Please add a comment about the parameters. Which one is input, which one is
output?

Why not just return scoped_ptr<EncodedAudioFrame> instead of using an output
pointer?

[pwestin, 2013/11/07 17:16:04]

it felt weird allowing the scoped ptr being empty and use that to check for
errors; just my preference  

+                         EncodedAudioFrame* audio_frame);
+
   // Schedule the next RTCP report.
   void ScheduleNextRtcpReport();
 
@@ -110,6 +114,8 @@ class AudioReceiver : public base::NonThreadSafe,
   base::TimeDelta time_offset_;
   base::TimeTicks time_first_incoming_packet_;
   uint32 first_incoming_rtp_timestamp_;
+  scoped_ptr<crypto::Encryptor> decryptor_;
+  std::string iv_mask_;
 
   std::list<AudioFrameEncodedCallback> queued_encoded_callbacks_;
 };