A game I played that would most of the time give me the webGL memory error has yet to give it to me a single time after doing this. And if it does give the error when I haven't done it, I just do it, reload and presto no error. Sure is a lot faster than restarting the whole system, or even just clearing the cache and restarting firefox.
Would be nice to know that the last few hours I spent going down a rabbit trail that eventually revealed this possible solution wasn't a complete waste of time, or rather that it could be of some help to the general community.
I didn't find the right solution from the internet.