The following code asserts on mozilla-central revision 9a230265bad5 (no options required):
Created attachment 586969 [details] [diff] [review]
The patch reports an error if gcparam tries to set maxBytes to a value less than the current gcBytes.
It should be noted that this code is part of the tests. In "tests/js1_6/extensions/regress-456826.js", line 59 it says "gcparam("maxBytes", 22000);".
https://hg.mozilla.org/integration/mozilla-inbound/rev/a85cf7f0d235 - I updated the test to use gcparam("maxBytes", gcparam("gcBytes")+4096)
Automatically extracted testcase for this bug was committed: