Reviewed by Darin Adler.

        Let WebKit generate a plug-in ID instead of having the plug-in host do it.

        * Plugins/Hosted/NetscapePluginHostManager.mm:
        (WebKit::NetscapePluginHostManager::instantiatePlugin):
        Create the plug-in proxy before instantiating the plug-in.
        
        * Plugins/Hosted/NetscapePluginInstanceProxy.h:
        (WebKit::NetscapePluginInstanceProxy::create):
        (WebKit::NetscapePluginInstanceProxy::setRenderContextID):
        (WebKit::NetscapePluginInstanceProxy::setUseSoftwareRenderer):
        * Plugins/Hosted/NetscapePluginInstanceProxy.mm:
        (WebKit::NetscapePluginInstanceProxy::NetscapePluginInstanceProxy):
        * Plugins/Hosted/WebKitPluginHost.defs:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@39315 268f45cc-cd09-0410-ab3c-d52691b4dbfc