Fix WebRTC transport to use single offer-answer exchange instead of two.

remoting/host/client_session_unittest.cc

Index: remoting/host/client_session_unittest.cc
diff --git a/remoting/host/client_session_unittest.cc b/remoting/host/client_session_unittest.cc
index 32da050c048e0e1e396097af5c3e47199689656f..d77ceea1b639d8bd50904783b656e8aee38aedb2 100644
--- a/remoting/host/client_session_unittest.cc
+++ b/remoting/host/client_session_unittest.cc
@@ -205,6 +205,7 @@ void ClientSessionTest::ConnectClientSession() {
   EXPECT_TRUE(connection_->clipboard_stub());
   EXPECT_TRUE(connection_->input_stub());
 
+  client_session_->CreateVideoStreams(client_session_->connection());
   client_session_->OnConnectionChannelsConnected(client_session_->connection());
 }