Chrome Version: 68.0.3424.0
OS: Linux and ChromeOS

What steps will reproduce the problem?
(1) Open Chrome with a touch device (you can simulate it with --touch-devices=??? on Linux)
(2) Enable the #enable-experimental-fullscreen-exit-ui flag
(3) Enter application fullscreen
(4) Long-press on the page and wait for ~3 seconds

What is the expected result?
The exit UI should timeout

What happens instead?
The exit UI doesn't timeout