Fix crasher with autofill infobar.
The "save credit card" information was deleted by the AutofillManager when the form is submitted but was still pointed to by the TabContents, causing a crasher when navigating.

BUG=50428
TEST=See steps in 56238.

Review URL: http://codereview.chromium.org/3466006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60095 0039d316-1c4b-4281-b951-d872f2087c98
int AutoFillManager::PackIDs(int cc_id, int profile_id) {
  DCHECK(cc_id <= std::numeric_limits<unsigned short>::max());
  DCHECK(profile_id <= std::numeric_limits<unsigned short>::max());

  return cc_id << std::numeric_limits<unsigned short>::digits | profile_id;
}

int AutoFillManager::PackIDs(int cc_id, int profile_id) {
  DCHECK(cc_id <= std::numeric_limits<unsigned short>::max());
  DCHECK(profile_id <= std::numeric_limits<unsigned short>::max());

  return cc_id << std::numeric_limits<unsigned short>::digits | profile_id;
}
