I think Google created Angular in part because of some problems with GWT. Of course some developers still uses GWT but others have switched to AngularJs and seems to think it is much more productive. And some combines Dart with Angular which really looks interesting.
GWT is open source and is being used / developed outside of Google, so it'll hardly be abandoned even if google left it. But Google is still using it heavily, see Inbox which just came out and uses GWT.
Also, angular and dart are slow as shit compared to GWT.
