Reviewed by Beth Dakin.

        Fixed <rdar://problem/4844855> Should clarify when to create clients in 
        the WebCore client API
        
        All clients must now be supplied as constructor arguments. This clarifies 
        when you need to create clients, and also guarantees that objects can't 
        (for the most part) be in a clientless state.

        Layout tests pass. No leaks reported.
        
        * bridge/mac/WebCoreFrameBridge.mm: I had to move some initialization up into
        WebKit to resolve circular dependencies at init time.

WebKit:

        Reviewed by Beth Dakin.

        Fixed <rdar://problem/4844855> Should clarify when to create clients in 
        the WebCore client API
        
        All clients must now be supplied as constructor arguments. This clarifies 
        when you need to create clients, and also guarantees that objects can't 
        (for the most part) be in a clientless state.

        Layout tests pass. No leaks reported.
        
        * WebCoreSupport/WebFrameBridge.mm: Shuffled around initialization and changed
        some arguments to resolve ciruclar dependencies at init time.
        (-[WebFrame _initWithWebFrameView:webView:bridge:]): We no longer call setClient
        here, because the client is set up at construction time.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@17918 268f45cc-cd09-0410-ab3c-d52691b4dbfc