GitLab

Set up an experiment to see the impact of always using the fast exit
path. For context, see https://groups.google.com/a/chromium.org/d/topic/chromium-dev/AMB2Y7Sqj48/discussion

Testing: launch with --enable-features=DesktopFastShutdown

BUG=653647

Review-Url: https://codereview.chromium.org/2528173003
Cr-Commit-Position: refs/heads/master@{#436328}