areweslimyet.com (a.k.a. AWSY) hosts the memory benchmark that the MemShrink team uses to detect memory consumption changes, and it automatically runs on every time mozilla-inbound is updated.
John Shoenick implemented support for measuring try builds, which means you can test the impact on memory consumption of a change you’ve made. The instructions are here, but note that you need access to Mozilla’s VPN in order to queue up a run. Ask in the #memshrink channel on IRC if you run into any problems.
Use the following try syntax to generate a suitable desktop build without running any of the usual try test suites.
try: -b o -p linux64 -u none -t none
At the moment, the best way to run it is to build (via the try server) an unmodified browser as a control, and also a second, modified version with your changes. You can then compare the two points easily.
It only works with Linux desktop builds. AWSY has a mobile page but custom runs for mobile are not yet available.