Add VideoLayout message.

remoting/host/security_key/gnubby_extension_session_unittest.cc

Index: remoting/host/security_key/gnubby_extension_session_unittest.cc
diff --git a/remoting/host/security_key/gnubby_extension_session_unittest.cc b/remoting/host/security_key/gnubby_extension_session_unittest.cc
index ceb76e1d54579c140b62a16f131e92ce1d805feb..2c64a53bdf3b32f5c0ba7fe1afb0ad8059f96c62 100644
--- a/remoting/host/security_key/gnubby_extension_session_unittest.cc
+++ b/remoting/host/security_key/gnubby_extension_session_unittest.cc
@@ -65,6 +65,8 @@ class TestClientStub : public protocol::ClientStub {
     run_loop_->Quit();
   }
 
+  void SetVideoLayout(const protocol::VideoLayout& layout) override {}
+
   // protocol::ClipboardStub implementation.
   void InjectClipboardEvent(const protocol::ClipboardEvent& event) override {}