Add TransportSession interface to prepare for WebRTC-based transport.

remoting/protocol/connection_to_client_unittest.cc

Index: remoting/protocol/connection_to_client_unittest.cc
diff --git a/remoting/protocol/connection_to_client_unittest.cc b/remoting/protocol/connection_to_client_unittest.cc
index 63c0abadcfda0f11b4ac4bc80f6634b3a42230f2..0dc9281e0b37b554f5e6f7172cc0220b673ae67a 100644
--- a/remoting/protocol/connection_to_client_unittest.cc
+++ b/remoting/protocol/connection_to_client_unittest.cc
@@ -74,10 +74,11 @@ TEST_F(ConnectionToClientTest, SendUpdateStream) {
 
   // Verify that something has been written.
   // TODO(sergeyu): Verify that the correct data has been written.
-  ASSERT_TRUE(
-      session_->fake_channel_factory().GetFakeChannel(kVideoChannelName));
-  EXPECT_FALSE(session_->fake_channel_factory()
-                   .GetFakeChannel(kVideoChannelName)->written_data().empty());
+  FakeStreamSocket* channel = session_->GetTransportSession()
+                                  ->GetStreamChannelFactory()
+                                  ->GetFakeChannel(kVideoChannelName);
+  ASSERT_TRUE(channel);
+  EXPECT_FALSE(channel->written_data().empty());
 
   // And then close the connection to ConnectionToClient.
   viewer_->Disconnect();