This code currently works for remote subframes assuming that nsIRemoteTab is implemented
by BrowserParent, but will break when nsIRemoteTab is only for a top-level BrowserParent.
What this code really wants is a content process ID to retarget the channel to. This
commit switches the interfaces to pass this around instead of nsIRemoteTab.
Differential Revision: https://phabricator.services.mozilla.com/D31435
--HG--
extra : rebase_source : be3303c2d38d704a6a1817fa45fd76700fae6287
extra : histedit_source : c7bf1e496f4328acc9ee70fcccdff98ea2cce5df