This patch adds (and hooks up) a new service so that HTTP channels marked as
"Throttleable" will periodically be Suspend()ed and Resume()d when more
important operations are going (such as a page load).
While this patch is not responsible for marking channels as "Throttleable",
the general idea is that these would be less-important channels - background
downloads, beacons, etc, and perhaps even resources known to be trackers.
MozReview-Commit-ID: HEZsxS04rRK
--HG--
extra : rebase_source : 03cce85fe7df782e1f6e2da9e5a99997b796aba2