You can see that WebP image format is supported by not only Chrome/Android but also Opera.
This site provides funny comparison of supported features from the various browsers.
For example, you can check W3C Navigation Timing JS supported browsers here.
Then, you can see which browser can use that module from the Akamai RUM(Real User Monitoring).
Also check below URLs for fun.
http://caniuse.com/#search=jpegxr (only supported by IE)
http://caniuse.com/#search=http2 (most of recent browsers are supporting)
http://caniuse.com/#search=spdy (more than HTTP/2 because it's older?)