Check out an example Android App showing Polymer components working on Android, everything loaded offline in a webview.
A simple app for FirefoxOS realized with AngularJS, Polymer and BuildingBlocks. Check it out @ GitHub.
At the moment the situation is pure madness! Web developing is pushing the throttle down! Google is developing several projects, beautiful ones, I’m a fan of AngularJS and I’m appreciating more and more their alpha project named Polymer.