Form control focus by click on a label should be handled as same as focus
by mouse down on the control.

This is a follow-up of Blink r153039.
Some form controls don't show focus rings by mouse press. Focus by click
on a label should have same bahavior.

BUG=265793

Review URL: https://chromiumcodereview.appspot.com/21321002

git-svn-id: svn://svn.chromium.org/blink/trunk@155315 bbb929c8-8fbe-4397-9dbb-9b2b20218538