Add support for GCM cipher suites from RFC 7714.

webrtc/api/peerconnection.cc

Index: webrtc/api/peerconnection.cc
diff --git a/webrtc/api/peerconnection.cc b/webrtc/api/peerconnection.cc
index a337d003dc808e51acd3fd25615b64b3df9d210f..4d64747c33379492631794ada51a9b9063800c7b 100644
--- a/webrtc/api/peerconnection.cc
+++ b/webrtc/api/peerconnection.cc
@@ -1584,6 +1584,7 @@ bool PeerConnection::GetOptionsForOffer(
   }
 
   session_options->rtcp_cname = rtcp_cname_;
+  session_options->crypto_options = factory_->options().crypto_options;
   return true;
 }
 
@@ -1611,6 +1612,7 @@ void PeerConnection::FinishOptionsForAnswer(
   if (session_->data_channel_type() == cricket::DCT_SCTP) {
     session_options->data_channel_type = cricket::DCT_SCTP;
   }
+  session_options->crypto_options = factory_->options().crypto_options;
 }
 
 bool PeerConnection::GetOptionsForAnswer(