Initially, Dart's developers focused on building a virtual machine that would run Dart code inside Chrome and other browsers, which would have allowed developers to write Web applications in Dart. No other browser makers made any significant moves to adopt Dart, and so the decision to not include it in Chrome pretty much seals its fate as a stand-alone programming language for the Web.
Dart remains fairly widely used within Google itself. The Google Ads business unit is one of the largest users of Dart, according to the company. It is also used for Google Fiber and the Google Express online store and for the internal business applications used by the Google sales team.