Make timezone editable

Fixes regression where timezone setting is disabled on enterprise devices.

BUG=347071
R=dpolukhin@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/181813004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253661 0039d316-1c4b-4281-b951-d872f2087c98
Update ServicesCustomizationDocument to match new design doc

Old ServicesCustomizationDocument is not used. This CL is preparation part for
new OEM customization. It should unblock work on applying wallpaper and default
apps so they could be done in parallel.

BUG=343589
TEST=unit_test
R=nkostylev@chromium.org

Review URL: https://codereview.chromium.org/178873002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253662 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253662