So in the pursuit of tracking down the WebGL leak...
My Acer notebook: well, it turns out it doesn't have a good enough video card to run WebGL (so the sites tell me when I try) so nevermind that comparison.
This same desktop machine I've been using, but under OpenSUSE 13.1 (I know, I haven't updated): Firefox 30.0 had no issues with the Cubemap and OpenRacer demos, updated to 36.0, still not having any issues with those two demos. I know Linux isn't the same bag as Windows, but this at least implies it's not my hardware and it's possibly not WebGL 2.0 itself since those would be the common threads.
While I was checking for the update for FF for OpenSUSE I noticed that FF for Windows has reached 36.0.1 so once back in Win7 I updated, then tried the Cubemap and OpenRacer demos...FireFox 36.0.1's WebGL has NO LEAK.
Task Manager says it occupies under 300mb when running those demos. Just in case some common element was 'fixed' in the FF updating, back to WF and... ugh, no, WF hit 2gb after a minute.
So it looks like something in the 36.0.1 code base resolved the WebGL issue, even if you haven't been able to identify what that thing is, so responding to something you'd said to me a day or two ago... Yes, looking forward to the next WF update based on the latest FF build. Edited by themushroom - 3/6/15 at 11:13am