[Chromium] Protect message ports from being deleted in V8MessageEvent::portsAccessorG...

[Chromium] Protect message ports from being deleted in V8MessageEvent::portsAccessorGetter
https://bugs.webkit.org/show_bug.cgi?id=68584

Patch by Sergey Glazunov <serg.glazunov@gmail.com> on 2011-09-21
Reviewed by Adam Barth.

Source/WebCore:

Test: fast/dom/message-port-deleted-by-accessor.html

* bindings/v8/custom/V8MessageEventCustom.cpp:
(WebCore::V8MessageEvent::portsAccessorGetter):

LayoutTests:

* fast/dom/message-port-deleted-by-accessor-expected.txt: Added.
* fast/dom/message-port-deleted-by-accessor.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@95689 268f45cc-cd09-0410-ab3c-d52691b4dbfc