That's actually the exact opposite of reality: Dart was a retention project for Lars Bak, and it was designed specifically with a focus on being able to make a fast VM implementation. The goal from the beginning was to have native support in browsers (they even got an ECMA standard for it!), and support compile-to-js as a polyfill until browsers had native support, but they couldn't convince any of the other vendors and so not even Chrome supported it. Some time after that, Lars Bak left Google.