Add ClientDimensions message to control channel.

remoting/protocol/host_control_dispatcher.cc

Index: remoting/protocol/host_control_dispatcher.cc
diff --git a/remoting/protocol/host_control_dispatcher.cc b/remoting/protocol/host_control_dispatcher.cc
index 4a78d0e21ecf24a474cac9cfe4eb12d294cbc16d..ec7d4a6792dc313d5888e498c950e2193da5b444 100644
--- a/remoting/protocol/host_control_dispatcher.cc
+++ b/remoting/protocol/host_control_dispatcher.cc
@@ -49,6 +49,8 @@ void HostControlDispatcher::OnMessageReceived(
 
   if (message->has_clipboard_event()) {
     clipboard_stub_->InjectClipboardEvent(message->clipboard_event());
+  } else if (message->has_client_dimensions()) {
+    host_stub_->NotifyClientDimensions(message->client_dimensions());
   } else {
     LOG(WARNING) << "Unknown control message received.";
   }