Most of this is fixing functions that in some cases return a value but then
can also run to completion without returning anything. ESLint 2 catches this
where previous versions didn't. Unless there was an obvious other choice I just
made these functions return undefined at the end which is effectively what
already happens.
MozReview-Commit-ID: KHYdAkRvhVr
While investigating bug 1248489, we discovered that some code paths in
AsyncShutdown could possibly be sensitive to exceptions being thrown
in unexpected places. This patch attempts to make AsyncShutdown more
robust to such exceptions.
MozReview-Commit-ID: 5ImL9YNVgQr
