8e1c242393
The `dart2js_options` flag was used in some other codepaths including "runtime=d8", this change allows us to pass --dart2js-options when using a browser runtime as well. Change-Id: I2864f52aff320ab3c2fbfb5a3b4bce34798a1792 Reviewed-on: https://dart-review.googlesource.com/8738 Reviewed-by: Emily Fortuna <efortuna@google.com>