Crash the network or desktop process when an unknown IPC message is received.

remoting/host/remoting_me2me_host.cc

Index: remoting/host/remoting_me2me_host.cc
diff --git a/remoting/host/remoting_me2me_host.cc b/remoting/host/remoting_me2me_host.cc
index e645f8115f0924e213ef8c49be171cf72277f641..bbf4546da35a12890c3e64545ad903ba04bf6afb 100644
--- a/remoting/host/remoting_me2me_host.cc
+++ b/remoting/host/remoting_me2me_host.cc
@@ -547,7 +547,11 @@ bool HostProcess::OnMessageReceived(const IPC::Message& message) {
                         DesktopSessionConnector::OnTerminalDisconnected)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
+
+  CHECK(handled) << "An unexpected IPC message received: type="
+                 << message.type();
   return handled;
+
 #else  // !defined(REMOTING_MULTI_PROCESS)
   return false;
 #endif  // !defined(REMOTING_MULTI_PROCESS)