Update Polymer components.

third_party/polymer/components/app-route/app-route.html

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 @license
 Copyright (c) 2016 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
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@@ skipping 82 matching lines @@
       properties: {
         /**
          * The URL component managed by this element.
          */
         route: {
           type: Object,
           notify: true
         },
 
         /**
-         * The pattern of slash-separated segments to match `path` against.
+         * The pattern of slash-separated segments to match `route.path` against.
          *
          * For example the pattern "/foo" will match "/foo" or "/foo/bar"
          * but not "/foobar".
          *
          * Path segments like `/:named` are mapped to properties on the `data` object.
          */
         pattern: {
           type: String
         },
 
@@ skipping 12 matching lines @@
          */
         queryParams: {
           type: Object,
           value: function() {
             return {};
           },
           notify: true
         },
 
         /**
-         * The part of `path` NOT consumed by `pattern`.
+         * The part of `route.path` NOT consumed by `pattern`.
          */
         tail: {
           type: Object,
           value: function() {return {path: null, prefix: null, __queryParams: null};},
           notify: true
         },
 
+        /**
+         * Whether the current route is active. True if `route.path` matches the 
+         * `pattern`, false otherwise.
+         */
         active: {
           type: Boolean,
           notify: true,
           readOnly: true
         },
 
         _queryParamsUpdating: {
           type: Boolean,
           value: false
         },
@@ skipping 254 matching lines @@
         }
         if (setObj.tail !== undefined) {
           this._pathEffector('tail', this.tail);
           this._notifyChange('tail');
         }
 
       }
     });
   })();
 </script>