Cast: Adding helper crypto classes

media/cast/video_receiver/video_receiver.h

Index: media/cast/video_receiver/video_receiver.h
diff --git a/media/cast/video_receiver/video_receiver.h b/media/cast/video_receiver/video_receiver.h
index ce47ebbeab0e6bfc3a1b45f3c6de069343dec02f..994d0228e3cef84ef04f1063ad8bd0d0e813c209 100644
--- a/media/cast/video_receiver/video_receiver.h
+++ b/media/cast/video_receiver/video_receiver.h
@@ -19,11 +19,7 @@
 #include "media/cast/rtcp/rtcp.h"
 #include "media/cast/rtp_receiver/rtp_receiver.h"
 #include "media/cast/rtp_receiver/rtp_receiver_defines.h"
-
-namespace crypto {
-class Encryptor;
-class SymmetricKey;
-}
+#include "media/cast/utility/cast_decryption_handler.h"
 
 namespace media {
 namespace cast {
@@ -114,9 +110,7 @@ class VideoReceiver : public base::NonThreadSafe,
   scoped_ptr<RtpReceiverStatistics> rtp_video_receiver_statistics_;
   base::TimeTicks time_last_sent_cast_message_;
   base::TimeDelta time_offset_;  // Sender-receiver offset estimation.
-  scoped_ptr<crypto::Encryptor> decryptor_;
-  scoped_ptr<crypto::SymmetricKey> decryption_key_;
-  std::string iv_mask_;
+  CastDecryptionHandler decryptor_;
   std::list<VideoFrameEncodedCallback> queued_encoded_callbacks_;
   bool time_incoming_packet_updated_;
   base::TimeTicks time_incoming_packet_;