According to justin, the way we're running mochitests right now in B2G is not out-of-process. In order to do so: "Ideally, you'd run the whole mochitest suite both from shell.xul and from inside <iframe mozbrowser>, which, if you have the right permissions set, will run OOP. See the bottom of dom/browser-element/mochitest/BrowserElementTestHelpers.js for the prefs you'd need to set, although many of these are probably already set correctly for you in b2g's existing prefs file."
See also bug 778072, which is the same thing, but for reftests.
Created attachment 648132 [details] [diff] [review] patch v0.1 This patch adds the necessary prefs to run mochitest in OOP mode on B2G. It also explicitly loads mochitest in the 'homescreen' mozbrowser element. I believe this patch works as intended. Before the patch, running mochitests resulted in only 1 B2G process: /system/b2g/b2g. Now, there are two, the former plus /system/b2g/plugin-container, and the latter's memory consumption varies considerably during the tests.
Comment on attachment 648132 [details] [diff] [review] patch v0.1 Okay!