Having these defined makes it easier to write class templates that manage dynamic roots automatically, as the function name doesn't depend on the type.

This is not tested or used, but I'm just putting it up for future reference.

Try push for the first patch: https://tbpl.mozilla.org/?tree=Try&rev=419ed6fdfe0b

Looks fine to me. We should rename Rooted to Local and name this Rooted though.

Jim: are you still working on these overloaded AddRoot() and RemoveRoot() functions for the JS API?

No. These were originally intended for bug 892643, which I no longer think is very important to fix, because 1) the motivating (to me!) use case went away, and 2) it's actually something that would be used less often than one might expect. See comments here: https://bugzilla.mozilla.org/show_bug.cgi?id=892643#c9

Based on the comments in bug 892643, this bug probably doesn't need to block the Exact Rooting milestone.

Bug 892643 gives us everything we need or want here.