Chrome Version: (copy from chrome://version) 60.0.3112.90
OS: (e.g. Win7, OSX 10.9.5, etc...) Ubuntu 14.04.5

What steps will reproduce the problem?
(1) Setup chrome-remote-desktop for multiple users
(2) Attempt to start chrome-remote-desktop for all
(3) Only one user will ever be able to see the host and connect

What is the expected result?

Multiple users being able to use connect to chrome-remote-desktop-host simultaneously.

What happens instead?

Xvfb-randr fails to start because it attempts to use the same file name for all users for the XKM file. The first user to compile the keymap and put it in the location in /tmp is the one who can use chrome-remote-desktop.

Please use labels and text to provide additional information.

2017-08-10 17:02:29,418:INFO:Using host_id: <REDACTED>
2017-08-10 17:02:29,419:INFO:Launching X server and X session.
2017-08-10 17:02:29,741:INFO:Starting /usr/bin/Xvfb-randr on display :21
[dix] Could not init font path element /usr/share/fonts/X11/misc, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/cyrillic, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/100dpi/:unscaled, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/75dpi/:unscaled, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/Type1, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/100dpi, removing from list!
[dix] Could not init font path element /usr/share/fonts/X11/75dpi, removing from list!
[dix] Could not init font path element /var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType, removing from list!
[xkb] Can't rename /tmp/filesVIum3 to /tmp/server-B20D7FC79C7F597315E3E501AEF10E0D866E8E92.xkm, error: Operation not permitted
[xkb] Can't rename /tmp/fileb7HvZ1 to /tmp/server-B20D7FC79C7F597315E3E501AEF10E0D866E8E92.xkm, error: Operation not permitted
XKB: Failed to compile keymap
Keyboard initialization failed. This could be a missing or incorrect setup of xkeyboard-config.

Fatal server error:
Failed to activate core devices.
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
xdpyinfo:  unable to open display ":21".
Traceback (most recent call last):
  File "/opt/google/chrome-remote-desktop/chrome-remote-desktop", line 1631, in <module>
    sys.exit(main())
  File "/opt/google/chrome-remote-desktop/chrome-remote-desktop", line 1552, in main
    desktop.launch_session(options.keep_env, args)
  File "/opt/google/chrome-remote-desktop/chrome-remote-desktop", line 736, in launch_session
    self._launch_x_server(x_args)
  File "/opt/google/chrome-remote-desktop/chrome-remote-desktop", line 653, in _launch_x_server
    self._launch_xvfb(display, x_auth_file, extra_x_args)
  File "/opt/google/chrome-remote-desktop/chrome-remote-desktop", line 573, in _launch_xvfb
    self._wait_for_x()
  File "/opt/google/chrome-remote-desktop/chrome-remote-desktop", line 549, in _wait_for_x
    raise Exception("Could not connect to X server.")
Exception: Could not connect to X server.
2017-08-10 17:02:40,065:INFO:Cleanup.
2017-08-10 17:02:40,066:INFO:Terminating X server
[0810/170240.080873:WARNING:remoting_user_session.cc(373)] Child did not exit normally

Solution?

The solution is to somehow force xkb to use a per-user filename for the keymap or force a per-user subdirectory inside /tmp for the X server.