Don't consume a user gesture when going to fullscreen

We meanwhile just exit fullscreen before opening a new window, so consuming
a user gesture is overzealous.

This revert r160739, r159021, and r158993

BUG=none
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/52423002

git-svn-id: svn://svn.chromium.org/blink/trunk@161085 bbb929c8-8fbe-4397-9dbb-9b2b20218538