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
bool BrowserView::CanActivate() const {
  if (!AppModalDialogQueue::GetInstance()->active_dialog())
    return true;

  MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&BrowserView::ActivateAppModalDialog,
                 activate_modal_dialog_factory_.GetWeakPtr()));
  return false;
}

bool BrowserView::CanActivate() const {
  if (!AppModalDialogQueue::GetInstance()->active_dialog())
    return true;

  MessageLoop::current()->PostTask(
      FROM_HERE,
      base::Bind(&BrowserView::ActivateAppModalDialog,
                 activate_modal_dialog_factory_.GetWeakPtr()));
  return false;
}
