Store xsrf token received with psuggest results.

Stores xsrf token in AutocompleteMatch search_terms_args for later use
in case the user triggers deletion of a suggestion.

BUG=312477

Review URL: https://codereview.chromium.org/54203008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238422 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238422