I was closely involved as CTO and then SVP of Engineering at Mozilla from the inceptions of both WebGL (originally Canvas 3D) and asm.js (see http://asmjs.org/ for docs), which led to the 4 day port via Emscripten or Unreal Engine 3 and Unreal Tournament from native to web and in Firefox at 60fps. This prefigured WebAssembly, which came in 2015 after it was clear from MS and the V8 team that one VM (not two as for Dart or PNaCL) would win.
Gary added the insight that system call overhead is higher than VM safety in one process (he may have exaggerated just a little) to predict migration of almost all native code. The general idea of a safe language VM+compiler being smaller and easier to verify than a whole OS+browser-native-codebase, as well as having lower security check overhead, I first heard articulated by Michael Franz of UCI, and it inspired my agenda at Mozilla that led to the current portable/multiply implemented JS+WebAssembly VM standard.
Gary added the insight that system call overhead is higher than VM safety in one process (he may have exaggerated just a little) to predict migration of almost all native code. The general idea of a safe language VM+compiler being smaller and easier to verify than a whole OS+browser-native-codebase, as well as having lower security check overhead, I first heard articulated by Michael Franz of UCI, and it inspired my agenda at Mozilla that led to the current portable/multiply implemented JS+WebAssembly VM standard.