Your buttons doesn't work for me on Chrome 36 / Mac OSX:
EDIT: I'm getting the feeling there might be a niche market for a cross-platform program that does this. QuickCast is slick, but Mac-only. Simplescreenrecorder works, but it's Linux-only. Running ffmpeg console commands might work, but it's a bit esoteric. Nvidia has a tool, but only for Nvidia card owners. And QuickTime is, well, QuickTime. Interesting...
Actually, it'd be nice to have a program that records WebM + uploads to Gfycat in one step.
(I also have LiteCap, QuickCast, ... but there are all really bad)