Google Closure Stylesheets Compiler

Implement a string concatenation gss function: concat(...)

This allows to dynamically construct urls, e.g.

@def HOST static.example.com
.img {
  background-image: url(concat('//', HOST, '/image.png');
}
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=105082418