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
int TabStripModel::GetIndexOfLastTabContentsOpenedBy(
    const NavigationController* opener, int start_index) const {
  DCHECK(opener);
  DCHECK(ContainsIndex(start_index));

  TabContentsDataVector::const_iterator end =
      contents_data_.begin() + start_index;
  TabContentsDataVector::const_iterator iter = contents_data_.end();
  TabContentsDataVector::const_iterator next;
  for (; iter != end; --iter) {
    next = iter - 1;
    if (next == end)
      break;
    if ((*next)->opener == opener)
      return static_cast<int>(next - contents_data_.begin());
  }
  return kNoTab;
}

int TabStripModel::GetIndexOfLastTabContentsOpenedBy(
    const NavigationController* opener, int start_index) const {
  DCHECK(opener);
  DCHECK(ContainsIndex(start_index));

  TabContentsDataVector::const_iterator end =
      contents_data_.begin() + start_index;
  TabContentsDataVector::const_iterator iter = contents_data_.end();
  TabContentsDataVector::const_iterator next;
  for (; iter != end; --iter) {
    next = iter - 1;
    if (next == end)
      break;
    if ((*next)->opener == opener)
      return static_cast<int>(next - contents_data_.begin());
  }
  return kNoTab;
}
