Reviewed by Anders and Kevin Decker.

        - fix <rdar://problem/5951130> REGRESSION: crash on quit after reopening windows from previous session

        * WebView/WebView.mm:
        (-[WebViewPrivate dealloc]): Fix assertions to not complain when fast teardown is used.
        (-[WebView _closePluginDatabases]): Factored out some common code from both versions of close.
        (-[WebView _closeWithFastTeardown]): Added an underscore to this method's name, since it's internal.
        Streamlined the code a bit. Added a line of code to set _private->closed (this is the bug fix).
        (-[WebView _close]): Changed for new method name and to use _closePluginDatabases.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@33968 268f45cc-cd09-0410-ab3c-d52691b4dbfc