Reviewed by Darin.
        
        Test case for:
        - various event cleanup, including fixing of the load event for iframes
        http://bugzilla.opendarwin.org/show_bug.cgi?id=7079

        * fast/events/iframe-object-onload-expected.txt: Added.
        * fast/events/iframe-object-onload.html: Added.

WebCore:

        Reviewed by Darin.

        - various event cleanup, including fixing of the load event for iframes
        http://bugzilla.opendarwin.org/show_bug.cgi?id=7079
        
        Specific changes:
        
        - don't bother to nil-check the document, a node can never have a null document now
        - move temp event forgetting from dispatchEvent to dispatchGenericEvent
        - pass event down using RefPtr::release() to avoid ref thrashing
        - support default handlers even for non-bubbling events (only on
          target node) and skip calling default event handler explicitly in
          callers
        - dispatch a whole separate load event to a frame document's containing frame
        - don't let propagationStopped prevent this new event
        - remove bogus security check for iframe onload

        * bridge/mac/MacFrame.mm:
        (WebCore::MacFrame::shouldClose):
        * khtml/xml/NodeImpl.cpp:
        (WebCore::NodeImpl::dispatchEvent):
        (WebCore::NodeImpl::dispatchGenericEvent):
        (WebCore::NodeImpl::dispatchWindowEvent):
        * khtml/xml/NodeImpl.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@12571 268f45cc-cd09-0410-ab3c-d52691b4dbfc