Change WebRTC SslCipher to be exposed as number only.

webrtc/p2p/base/dtlstransportchannel.h

Index: webrtc/p2p/base/dtlstransportchannel.h
diff --git a/webrtc/p2p/base/dtlstransportchannel.h b/webrtc/p2p/base/dtlstransportchannel.h
index ddedcbcaa8bd81784f979b68d41b25a42bbbbff8..d8e791c021af77880e01fc3f9e7d5207e4af6da5 100644
--- a/webrtc/p2p/base/dtlstransportchannel.h
+++ b/webrtc/p2p/base/dtlstransportchannel.h
@@ -144,7 +144,7 @@ class DtlsTransportChannelWrapper : public TransportChannelImpl {
   bool SetSslRole(rtc::SSLRole role) override;
 
   // Find out which DTLS cipher was negotiated
-  bool GetSslCipher(std::string* cipher) override;
+  bool GetSslCipher(rtc::SslCipher* cipher) override;
 
   // Once DTLS has been established, this method retrieves the certificate in
   // use by the remote peer, for use in external identity verification.