Code review comment for lp:~nick-dedekind/qtmir/prompt-in-prompt

To test:
https://code.launchpad.net/~nick-dedekind/+junk/trusted_sessions_app
make & install

start clock app

in ssh:
MIR_SOCKET=$XDG_RUNTIME_DIR/mir_socket_trusted trust-session-demo-trusted-helper -p `pgrep -f clock`

in another ssh:
MIR_SOCKET=$XDG_RUNTIME_DIR/mir_socket_trusted trust-session-demo-trusted-helper -p `pgrep -f trust-session-demo-app`