chromeos: fix bug where "aw snap" page replaces first tab if it was a NTP when closing window with > 1 tab.

BUG=chromium-os:12088
TEST=verify bug per bug report.
Review URL: http://codereview.chromium.org/6882058

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@83031 0039d316-1c4b-4281-b951-d872f2087c98
void TabStripModel::ForgetOpenersAndGroupsReferencing(
    const NavigationController* tab) {
  for (TabContentsDataVector::const_iterator i = contents_data_.begin();
       i != contents_data_.end(); ++i) {
    if ((*i)->group == tab)
      (*i)->group = NULL;
    if ((*i)->opener == tab)
      (*i)->opener = NULL;
  }
}

void TabStripModel::ForgetOpenersAndGroupsReferencing(
    const NavigationController* tab) {
  for (TabContentsDataVector::const_iterator i = contents_data_.begin();
       i != contents_data_.end(); ++i) {
    if ((*i)->group == tab)
      (*i)->group = NULL;
    if ((*i)->opener == tab)
      (*i)->opener = NULL;
  }
}
