Polymer elements added to third_party/polymer.

third_party/polymer/components/core-media-query/core-media-query.html

+<!--
+Copyright (c) 2014 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
+-->
+<!--
+/**
+ * @group Polymer Core Elements
+ * @element core-media-query
+ * @status beta
+ * @homepage github.io
+ *
+ * core-media-query can be used to data bind to a CSS media query.
+ * The "query" property is a bare CSS media query.
+ * The "queryMatches" property will be a boolean representing if the page matches that media query.
+ *
+ * core-media-query uses media query listeners to dynamically update the "queryMatches" property.
+ * A "core-media-change" event also fires when queryMatches changes.
+ *
+ * Example:
+ *
+ *      <core-media-query query="max-width: 640px" queryMatches="{{phoneScreen}}"></core-media-query>
+ *
+ */
+
+ /**
+  * Fired when the media query state changes
+  *
+  * @event core-media-change
+  */
+-->
+<link rel="import" href="../polymer/polymer.html">
+
+<polymer-element name="core-media-query" attributes="query queryMatches">
+  <template>
+    <style>
+      :host {
+        display: none;
+      }
+    </style>
+  </template>
+  <script>
+    Polymer('core-media-query', {
+
+      /**
+       * The Boolean return value of the media query
+       *
+       * @attribute queryMatches
+       * @type Boolean
+       * @default false
+       */
+      queryMatches: false,
+
+      /**
+       * The CSS media query to evaulate
+       *
+       * @attribute query
+       * @type string
+       * @default ''
+       */
+      query: '',
+      ready: function() {
+        this._mqHandler = this.queryHandler.bind(this);
+        this._mq = null;
+      },
+      queryChanged: function() {
+        if (this._mq) {
+          this._mq.removeListener(this._mqHandler);
+        }
+        var query = this.query;
+        if (query[0] !== '(') {
+          query = '(' + this.query + ')';
+        }
+        this._mq = window.matchMedia(query);
+        this._mq.addListener(this._mqHandler);
+        this.queryHandler(this._mq);
+      },
+      queryHandler: function(mq) {
+        this.queryMatches = mq.matches;
+        this.asyncFire('core-media-change', mq);
+      }
+    });
+  </script>
+</polymer-element>