Well, I hope that the following two profiler bugs land before then:

Bug 1008435 - [e10s] Port the built-in Gecko profiler to e10s https://bugzilla.mozilla.org/show_bug.cgi?id=1008435

Bug 974832 - WebGL EXT_disjoint_timer_query may now be implemented https://bugzilla.mozilla.org/show_bug.cgi?id=974832