One of the "metrics" of Firefox memory usage is "close a bunch of tabs and see how much memory usage goes down". We should be measuring this as part of Talos.

Talos (Tp) currently doesn't open a lot of tabs at once. So let's make this an endurance test instead. (Or did we specifically want to use the Talos page set?)

The particular pageset used doesn't really matter to me as long as it's representative of the web. Of course, it seems like a good idea to curate as few pagesets as possible ...

I had bits and pieces of a test that would open each page of tp into a separate tab and then close them - is that the sort of thing that you are looking for? I believe that the missing components would be in determining the memory footprint change over the course of the test.

This would be covered by the 'membuster' endurance test. See bug 669613.