Cast: Added support for AES-CTR crypto.

media/cast/audio_sender/audio_sender.h

Index: media/cast/audio_sender/audio_sender.h
diff --git a/media/cast/audio_sender/audio_sender.h b/media/cast/audio_sender/audio_sender.h
index ca1fffb37f2416664f5dae8a3a6cbad7997b1287..9b98cabba6886a6a18578a366d1ebac2a26e22b4 100644
--- a/media/cast/audio_sender/audio_sender.h
+++ b/media/cast/audio_sender/audio_sender.h
@@ -12,6 +12,7 @@
 #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/rtcp/rtcp.h"
@@ -66,6 +67,11 @@ class AudioSender : public base::NonThreadSafe,
   void ResendPackets(
       const MissingFramesAndPacketsMap& missing_frames_and_packets);
 
+  // Caller must allocate the destination |encrypted_frame|. The data member
+  // will be resized to hold the encrypted size.
+  bool EncryptAudioFrame(const EncodedAudioFrame& audio_frame,
+                         EncodedAudioFrame* encrypted_frame);
+
   void ScheduleNextRtcpReport();
   void SendRtcpReport();
 
@@ -78,6 +84,8 @@ class AudioSender : public base::NonThreadSafe,
   scoped_ptr<LocalRtpSenderStatistics> rtp_audio_sender_statistics_;
   scoped_ptr<LocalRtcpAudioSenderFeedback> rtcp_feedback_;
   Rtcp rtcp_;
+  scoped_ptr<crypto::Encryptor> encryptor_;
+  std::string iv_mask_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioSender);
 };