Cast: Adding helper crypto classes

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 5c7016adace207d48c53e6a0597ccb1b37481599..74c41b92b134248b4091bc7e1a661cc3a2446cf1 100644
--- a/media/cast/audio_receiver/audio_receiver.h
+++ b/media/cast/audio_receiver/audio_receiver.h
@@ -18,11 +18,7 @@
 #include "media/cast/cast_receiver.h"
 #include "media/cast/rtcp/rtcp.h"                          // RtcpCastMessage
 #include "media/cast/rtp_receiver/rtp_receiver_defines.h"  // RtpCastHeader
-
-namespace crypto {
-class Encryptor;
-class SymmetricKey;
-}
+#include "media/cast/transport/utility/transport_encryption_handler.h"
 
 namespace media {
 namespace cast {
@@ -132,9 +128,7 @@ 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_;
-  scoped_ptr<crypto::SymmetricKey> decryption_key_;
-  std::string iv_mask_;
+  transport::TransportEncryptionHandler decryptor_;
   base::TimeTicks last_playout_time_;
 
   std::list<AudioFrameEncodedCallback> queued_encoded_callbacks_;