Reviewed by Eric.

    Reviewed by Eric.

        <rdar://problem/3694093> -[WebBasePluginPackage finalize] is incorrect; design change needed

        Call -unload on plug-in packages instead of relying on -dealloc/-finalize to do it.  Currently
        the only place plug-in packages are deallocated is when refreshing the set of plugins, as when
        handling JavaScript's navigator.plugins.refresh().

        * Plugins/WebBasePluginPackage.m:
        (-[WebBasePluginPackage dealloc]):
        Assert that the plug-in has been unloaded by the time -dealloc is called.
        (-[WebBasePluginPackage finalize]):
        ditto

        * Plugins/WebPluginDatabase.m:
        (-[WebPluginDatabase refresh]):
        Call -unload on the plug-in packages before releasing them.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@13523 268f45cc-cd09-0410-ab3c-d52691b4dbfc