It serves no purpose, and it's annoying when the presubmit checks take more than
2-3 seconds because I always switch off to another window, so I come back
minutes later seeing this prompt waiting for me.

R=stip@chromium.org
BUG=

Review URL: https://codereview.chromium.org/407413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@285071 0039d316-1c4b-4281-b951-d872f2087c98