Adding number of users to ChromeOS crash record

BUG=330217
TEST=none

Review URL: https://codereview.chromium.org/137753007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245408 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245408