GitLab

Now the feature is approved to roll out into Stable channel,
let me flip the feature flag to be enabled by default.

This is a required process to launch the feature through the field study,
and should be done before the feature is rolled out to 100%.

BUG=591245

Review-Url: https://codereview.chromium.org/2296603002
Cr-Commit-Position: refs/heads/master@{#415569}