Don't re-enable or send values for disabled controls

BUG=307692
R=armansito@chromium.org, pneubeck@chromium.org

Review URL: https://codereview.chromium.org/27578004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229170 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229170