GitLab

Use overlay scrollbars in athena, for both views and content.

BUG=398883
R=oshima@chromium.org, sky@chromium.org

Review URL: https://codereview.chromium.org/428583003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287449 0039d316-1c4b-4281-b951-d872f2087c98