Use Menlo if available.

appengine/chromium_rietveld/new_static/components/cr-linkified-text.html

 <!-- Copyright (c) 2014 The Chromium Authors. All rights reserved.
 Use of this source code is governed by a BSD-style license that can be
 found in the LICENSE file. -->
 
 <script src="../lib/ba-linkify.js"></script>
 <script src="../link_text_parser.js"></script>
 
 <polymer-element name="cr-linkified-text" attributes="text">
     <template><link rel="stylesheet" href="common.css"><style>
         :host([pre]) {
             white-space: pre-wrap;
             word-wrap: break-word;
-            font-family: Monaco, monospace;
+            font-family: Menlo, Monaco, monospace;
         }
 
         img {
             margin: 0.5em 16px;
         }
     </style><div id="output"></div></template>
     <script>
     Polymer("cr-linkified-text", {
         created: function() {
             this.text = "";
@@ skipping 21 matching lines @@
                     output.appendChild(a);
                 } else {
                     output.appendChild(document.createTextNode(text));
                 }
             });
             parser.parse(newValue);
         },
     });
   </script>
 </polymer-element>