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 Browser::DidNavigateMainFramePostCommit(WebContents* web_contents) {
  if (web_contents == chrome::GetActiveWebContents(this))
    UpdateBookmarkBarState(BOOKMARK_BAR_STATE_CHANGE_TAB_STATE);
}

void Browser::DidNavigateMainFramePostCommit(WebContents* web_contents) {
  if (web_contents == chrome::GetActiveWebContents(this))
    UpdateBookmarkBarState(BOOKMARK_BAR_STATE_CHANGE_TAB_STATE);
}
