I don't have a complete solution yet, but I can share some links:

https://github.com/azul3d/issues/issues/29 - Very relevant discussion with good resources/links/info.

https://github.com/ajhager/engi - 2D game library for Go with desktop/browser/android targets.

https://github.com/shurcooL/play/tree/master/57 - Simple WebGL/GopherJS render triangle demo.

https://github.com/shurcooL/play/tree/master/58 - Unfinished attempt to make the above compiled to two desktop/browser targets.