Fixing focus highlight on high DPI devices for accessibility

The name seems rather odd, but I couldn't come up with something better...

BUG=320756
TEST=visual

Review URL: https://codereview.chromium.org/78803002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238185 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238185