Created attachment 534074 [details] [diff] [review] v1 FeedWriter holds a number of XPCOM objects alive through its prototype. These shouldn't live on the prototype, but on the instances. The prototype stays alive until shutdown, so it leads to bloat and sometimes to leaks because the CC can't collect any cycles involving objects held by FeedWriter.prototype.
Comment on attachment 534074 [details] [diff] [review] v1 rs=me, though I really don't understand why this fixes things. Would love an explanation for that.
I can't reproduce this anymore, so let's not do this since we don't understand how it could fix anything.