D is known for having an extremely fast compiler. In fact, Walter Bright wrote one of the fastest C++ compilers (the Digital Mars C++ compiler) before he wrote D.

For chromium, the most important concern will be runtime speed, more than compile time

Languages with native support for modules can have both.

Lets see how C++20 will improve the situation.

That, and most people who are compiling it are chromium developers, who will be using dirty builds and so have relatively quick compiles.

Think Delphi and .NET Native compile times.

I assume you are using ccache?