You can check it out by
- Opening up Chrome's developer tools (3 bar menu in upper right, Tools, Developer Tools)
- Opening up the options (gear menu in bottom right)
- Enabling 'Show FPS Meter' in the rendering section.
Or, in about:flags you can enable it always.
It's handy to see, e.g. when you are missing some frames and oscillating between 30 and 60fps: