Change WebRTC SslCipher to be exposed as number only.

webrtc/p2p/base/transportchannelproxy.cc

Index: webrtc/p2p/base/transportchannelproxy.cc
diff --git a/webrtc/p2p/base/transportchannelproxy.cc b/webrtc/p2p/base/transportchannelproxy.cc
index 74d1e1db762c016525ad7f0f22a2c73ea70ef626..e75bf049cf6bb8cfd256c7f7e534c42db9813651 100644
--- a/webrtc/p2p/base/transportchannelproxy.cc
+++ b/webrtc/p2p/base/transportchannelproxy.cc
@@ -181,7 +181,7 @@ bool TransportChannelProxy::GetSrtpCipher(std::string* cipher) {
   return impl_->GetSrtpCipher(cipher);
 }
 
-bool TransportChannelProxy::GetSslCipher(std::string* cipher) {
+bool TransportChannelProxy::GetSslCipher(rtc::SslCipher* cipher) {
   ASSERT(rtc::Thread::Current() == worker_thread_);
   if (!impl_) {
     return false;