Fix bug in moveNext where it was using equality instead of assignment.
Fix bug in moveNext where it was using equality instead of assignment.

Closes #299

Global Presubmit: https://test.corp.google.com/ui#id=OCL:206864816:BASE:206866852:1533089538920:84f691b

PiperOrigin-RevId: 206869788

angulardart/angular_components,angulardart/angular_components,angulardart/angular_components