Reviewed by Geoffrey Garen.

        Make DOMAbstractView have a weak reference to the Frame instead of ref'ing
        the DOMWindow.

        To ensure that the WindowScriptObject (which is a DOMAbstractView) stays valid
        after a navigation once the split window is completed, the DOMAbstractView must
        wrap the Frame instead of a DOMWindow since the DOMWindow will change.

        * WebCore.xcodeproj/project.pbxproj:
        * bindings/objc/DOMAbstractView.mm: Added.
        (-[DOMAbstractView dealloc]):
        (-[DOMAbstractView finalize]):
        (-[DOMAbstractView document]):
        (-[DOMAbstractView _disconnectFrame]):
        (-[DOMAbstractView WebCore::]):
        (-[DOMAbstractView _initWithFrame:WebCore::]):
        (+[DOMAbstractView _wrapAbstractView:WebCore::]):
        Add custom implementation to implement weak reference semantics.

        * bindings/objc/DOMAbstractViewFrame.h: Added.
        Declare the [DOMAbstractView _d...