Running eslint with --fix didn't fix many of the issues. The majority here had to be fixed by hand but a significant majority of the issues were related to a few files that I was able to use find-and-replace with. I regret not making this in to separate commits of the hand-fixes and the fixes from --fix but I don't recall --fix fixing any of the issues.
MozReview-Commit-ID: ANyg2qfo3Qx
This changes the `relatedBrowser` property which held a <xul:browser> to the
more explicit `sameProcessAsFrameLoader` which takes an nsIFrameLoader.
This clarifies the purpose of the property and also (by switching to the frame
loader) makes it easier to set in some contexts.
MozReview-Commit-ID: LnEvSP8zkto
This patch also makes sure that we correctly grab a weak reference to the
related window instead of just setting a "relatedBrowser" property directly on
the JS object (which shadows the XBL property getter).
MozReview-Commit-ID: 97VQyCoY1Cj
