Upgrade to 1.0 and switch clients to dom-repeat where needed.

third_party/polymer/v0_8/components/iron-signals/iron-signals.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">
+
+<script>
+(function(){
+/**
+`iron-signals` provides basic publish-subscribe functionality.
+
+Note: avoid using `iron-signals` whenever you can use
+a controller (parent element) to mediate communication
+instead.
+
+To send a signal, fire a custom event of type `iron-signal`, with
+a detail object containing `name` and `data` fields.
+
+    this.fire('iron-signal', {name: 'hello', data: null});
+
+To receive a signal, listen for `iron-signal-<name>` event on a
+`iron-signals` element.
+
+  <iron-signals on-iron-signal-hello="{{helloSignal}}">
+
+You can fire a signal event from anywhere, and all
+`iron-signals` elements will receive the event, regardless
+of where they are in DOM.
+
+@demo demo/index.html
+*/
+  Polymer({
+    is: 'iron-signals',
+
+    attached: function() {
+      signals.push(this);
+    },
+    detached: function() {
+      var i = signals.indexOf(this);
+      if (i >= 0) {
+        signals.splice(i, 1);
+      }
+    }
+  });
+
+  // private shared database
+  var signals = [];
+
+  // signal dispatcher
+  function notify(name, data) {
+    // convert generic-signal event to named-signal event
+    var signal = new CustomEvent('iron-signal-' + name, {
+      // if signals bubble, it's easy to get confusing duplicates
+      // (1) listen on a container on behalf of local child
+      // (2) some deep child ignores the event and it bubbles
+      //     up to said container
+      // (3) local child event bubbles up to container
+      // also, for performance, we avoid signals flying up the
+      // tree from all over the place
+      bubbles: false,
+      detail: data
+    });
+    // dispatch named-signal to all 'signals' instances,
+    // only interested listeners will react
+    signals.forEach(function(s) {
+      s.dispatchEvent(signal);
+    });
+  }
+
+  // signal listener at document
+  document.addEventListener('iron-signal', function(e) {
+    notify(e.detail.name, e.detail.data);
+  });
+
+})();
+</script>