Import Polymer 0.8 and several key elements.

third_party/polymer/v0_8/components/paper-behaviors/paper-button-behavior.html

+<!--
+@license
+Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
+This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
+The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
+The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
+Code distributed by Google as part of the polymer project is also
+subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
+-->
+
+<link rel="import" href="../polymer/polymer.html">
+<link rel="import" href="../iron-behaviors/iron-button-state.html">
+
+<script>
+
+  Polymer.PaperButtonElevation = {
+
+    properties: {
+
+      _elevation: {
+        type: Number
+      }
+
+    },
+
+    _calculateElevation: function() {
+      var e = 1;
+      if (this.disabled || !this.raised) {
+        e = 0;
+      } else if (this.active || this.pressed) {
+        e = 2;
+      } else if (this.focused) {
+        e = 3;
+      }
+      this._elevation = e;
+    }
+
+  };
+
+  Polymer.PaperButtonBehavior = [
+    Polymer.IronControlState,
+    Polymer.IronButtonState,
+    Polymer.PaperButtonElevation
+  ];
+
+</script>