UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:51.0) Gecko/20100101 Firefox/51.0

Steps to reproduce the problem:
1. Add a bunch of rules to the Mozilla sandbox code.  (This is a Chromium issue -- see below)
2. When a low level rule is used, Firefox will crash.

What is the expected behavior?
No amount of rules should cause a crash.

What went wrong?
Quick summary: Firefox uses the Chromium sandbox code.  After adding some rules, the sandbox low level policy buffer trashes itself.

The offending Chromium sandbox code is here: 
https://chromium.googlesource.com/chromium/src/sandbox/+/master/win/src/policy_low_level.cc#69

I have a fix for the issue in a patch in the Firefox bug report:
https://bugzilla.mozilla.org/show_bug.cgi?id=1299611

The patch uses a Mozilla ASSERT macro but is otherwise fine for your code base.  Unfortunately, the "test" case I wrote is Firefox-specific but someone more Chromium-familiar should be able to reproduce the issue, which you will see is a clear bug, without Firefox.  The Firefox test code is also in the bugzilla report.

Did this work before? N/A 

Chrome version: <Copy from: 'about:version'>  Channel: n/a
OS Version: Windows 10
Flash Version: Shockwave Flash 22.0 r0