Changes

See {{bug|710359}}. In the web-gaming era, it will not be tolerable that just having a GMail tab on the side severely harms FPS in a game in another tab. This should have been solved by electrolysis ( = process separation), but it's on hold. There doesn't seem to be much else to do about that For now, though perhaps {{bug|712731}} can help; see also posts in mozilla.dev.platform. Also, this isn't entirely JavaScript specificand {{bug|supersnappy}} aim to mitigate the problem.