[third_party] add polymer 1.2.3

polymer_1.2.3/bower_components/paper-styles/demo-pages.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-flex-layout/iron-flex-layout.html">
 
 <link rel="import" href="color.html">
 <link rel="import" href="typography.html">
 <link rel="import" href="shadow.html">
 
 <style is="custom-style">
 
   body {
-    font-family: 'Roboto', 'Noto', sans-serif;
+    @apply(--paper-font-common-base);
     font-size: 14px;
     margin: 0;
     padding: 24px;
     background-color: var(--paper-grey-50);
   }
 
   .horizontal-section-container {
     @apply(--layout-horizontal);
     @apply(--layout-center-justified);
     @apply(--layout-wrap);
@@ skipping 30 matching lines @@
   code {
     color: var(--google-grey-700);
   }
 
   /* TODO: remove this hack and use horizontal-section-container instead */
   body > div.layout.horizontal.center-justified {
     @apply(--layout-wrap);
   }
 
 </style>