Import Polymer 0.8 and several key elements.

third_party/polymer/v0_8/components-chromium/iron-behaviors/demo/simple-button-extracted.js

+
+
+    Polymer({
+
+      behaviors: [
+        Polymer.IronControlState,
+        Polymer.IronButtonState
+      ],
+
+      ready: function() {
+        if (!this.hasAttribute('role')) {
+          this.setAttribute('role', 'button');
+        }
+      }
+
+    });
+
+