[rAc - libaddressinput] slay another helper class

remove AddressValidator; the functionality will be added to AddressValidator

BUG=none

Review URL: https://codereview.chromium.org/125633003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@243430 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 243430