GitLab

BUG=405957
TEST=SplitViewControllerTest.SplitModeActivation

Review URL: https://codereview.chromium.org/488153003

Cr-Commit-Position: refs/heads/master@{#291400}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@291400 0039d316-1c4b-4281-b951-d872f2087c98