Fixed <rdar://problem/5238177> Continuing after hitting breakpoint doesn't 
        execute the next step.
        
        No test because the only code affected is the debugger, and none of the
        relevant API is exported.
        
        Reverted an accidental change in 21324 that caused originRootObject for
        the window object always to be 0. We could probably just remove the debugger's
        dependency on originRootObject, but I wanted to be safe.

        * page/mac/FrameMac.mm:
        (WebCore::Frame::windowScriptObject):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@21933 268f45cc-cd09-0410-ab3c-d52691b4dbfc