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 LoadURL(TabContents* con, const std::wstring& url) {
    controller().LoadURL(GURL(WideToUTF16(url)), GURL(), PageTransition::LINK);
  }

  void LoadURL(TabContents* con, const std::wstring& url) {
    controller().LoadURL(GURL(WideToUTF16(url)), GURL(), PageTransition::LINK);
  }
