I've backported upstream commit 2538:3f78d5e894bc from http://hg.mozilla.org/releases/mozilla-1.9.1/ which carries a similar change and also clarifies the macro names and comments.
I've backported upstream commit 2538:3f78d5e894bc from http:// hg.mozilla. org/releases/ mozilla- 1.9.1/ which carries a similar change and also clarifies the macro names and comments.