* Get the RefCounting of WebCore::Frame right and make sure that both QWebFrame
  and WebCore::Frame get destroyed if we leave site with subframes and on the
  end of the application.
* Use adoptRef in FrameLoaderClientQt::createFrame to get the refs right for subframes. We
  do not want to add an extra reference. Without this we are leaking subframes.
* Assume that the lifetime of a Frame and FrameLoader are the same, when the Frame is gone
  we want to destroy the QWebFrame (e.g. on a page with subframes). Add delete m_webFrame
  in the frameLoaderDestroyed method to do that.
* If we happen to delete the QWebFrame before the FrameLoaderClientQt we set m_webFrame to
  zero in the FrameLoaderClientQt to avoid bad things.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@31521 268f45cc-cd09-0410-ab3c-d52691b4dbfc