Google announced Brotli in September of last year. A few days ago it was veteran game developer Rich Geldreich talking about how Brotli is one of two new compression codecs that could obsolete Zlib. The news now is that Google is moving ahead with Brotli support in Chrome.
Brotli has already been supported on the Mozilla side since Firefox 44 while with Chrome it's planned for the next stable release, Chrome 49. Of course, to benefit from Brotli you need to have a server that supports compressing the content in the format. Of which, right now there are just out-of-tree patches/projects for compressing content with Brotli. Google has published some patches for supporting it with nginx but not yet for Apache. Another restriction is that Brotli is only being exposed on Firefox and Chrome for HTTPS web-pages.
More details on the Chrome Brotli plans via this mailing list post. If you want to learn more about this open-source data compression library, there is Wikipedia.