Change WebRTC SslCipher to be exposed as number only.

webrtc/p2p/base/p2ptransportchannel.h

Index: webrtc/p2p/base/p2ptransportchannel.h
diff --git a/webrtc/p2p/base/p2ptransportchannel.h b/webrtc/p2p/base/p2ptransportchannel.h
index 92969c8b7e0436b798af444bb229ce678809a30e..a2e29af7d94da9016309039eae62fc9bef76cb96 100644
--- a/webrtc/p2p/base/p2ptransportchannel.h
+++ b/webrtc/p2p/base/p2ptransportchannel.h
@@ -114,7 +114,7 @@ class P2PTransportChannel : public TransportChannelImpl,
   bool GetSrtpCipher(std::string* cipher) override { return false; }
 
   // Find out which DTLS cipher was negotiated.
-  bool GetSslCipher(std::string* cipher) override { return false; }
+  bool GetSslCipher(uint16_t* cipher) override { return false; }
 
   // Returns null because the channel is not encrypted by default.
   rtc::scoped_refptr<rtc::RTCCertificate> GetLocalCertificate() const override {