GitLab

Rapidly updating notifications (like progressbar indicators) can
be hard to interact with if the state resets with each update.

BUG=368025

Review URL: https://codereview.chromium.org/273173003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@272609 0039d316-1c4b-4281-b951-d872f2087c98