Polymer 0.9.5
The class names to use are polymer-veiled
(hidden) and polymer-unveil
(during unveil transition)
If it is different than in Polymer.js it is probably subject of change but as of PolymerDart 0.9.0 it should work.
The relevant code is in packages/polymer/src/boot.dart
.
Polymer 0.10.0
Polymer 0.10.0-pre.1 uses already the unresolved
attribute like explained here
Polymer - Styling reference - FOUC prevention
You need to add a version constraint in pubspec.yaml
to get the development version like
polymer: ">=0.10.0-pre.1"