Remove TabContents from TabStripModelObserver::TabDetachedAt.

BUG=107201
TEST=no visible change


Review URL: https://chromiumcodereview.appspot.com/11293205

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@167122 0039d316-1c4b-4281-b951-d872f2087c98
void TabStripModel::InternalCloseTab(WebContents* contents,
                                     int index,
                                     bool create_historical_tabs) {
  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
                    TabClosingAt(this, contents, index));

  if (create_historical_tabs)
    delegate_->CreateHistoricalTab(contents);

  TabContents* tab_contents = TabContents::FromWebContents(contents);
  DCHECK(tab_contents);
  delete tab_contents;
}

void TabStripModel::InternalCloseTab(WebContents* contents,
                                     int index,
                                     bool create_historical_tabs) {
  FOR_EACH_OBSERVER(TabStripModelObserver, observers_,
                    TabClosingAt(this, contents, index));

  if (create_historical_tabs)
    delegate_->CreateHistoricalTab(contents);

  TabContents* tab_contents = TabContents::FromWebContents(contents);
  DCHECK(tab_contents);
  delete tab_contents;
}
