[9/8u60] Request for review: JDK-8087932 [Mac] intermittent crash on exit in WebView

[Anton V. Tarasov]

Hi Kevin,

Please review the fix:

JBS: https://bugs.openjdk.java.net/browse/JDK-8087932
webrev: http://cr.openjdk.java.net/~ant/JDK-8087932/webrev.0

Thanks,
Anton.