Fix for Radar bug 4478840, Safari should not reduce null events sent to

    Fix for Radar bug 4478840, Safari should not reduce null events sent to
        plug-ins in windows that are inactive but visible.

        With this fix you can view videos in visible background windows on YouTube
        (for example) and not see any drop in frame rate.

        Reviewed by timo

        * Plugins/WebBaseNetscapePluginView.m:
        (-[WebBaseNetscapePluginView restartNullEvents]):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@15861 268f45cc-cd09-0410-ab3c-d52691b4dbfc