Use Menlo if available.

appengine/chromium_rietveld/new_static/components/cr-user-autocomplete.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. -->
 
 <link rel="import" href="cr-keyboard.html">
 
 <polymer-element name="cr-user-autocomplete" attributes="value">
     <template>
         <style>
             :host {
                 -webkit-user-select: none;
             }
 
             #completions {
                 position: absolute;
                 border: 1px solid #dcdcdc;
                 border-top: none;
                 background-color: white;
                 left: 0;
                 right: 0;
                 margin: 0 16px;
-                font-family: Monaco, monospace;
+                font-family: Menlo, Monaco, monospace;
                 font-size: 0.9em;
                 z-index: 1;
                 cursor: default;
             }
 
             .completion {
                 padding: 0.5em 16px;
             }
 
             .selected {
@@ skipping 130 matching lines @@
                 this.didComplete = true;
             },
             resetAutocomplete: function() {
                 this.completions = [];
                 this.termRange = {};
                 this.active = false;
             },
         });
     </script>
 </polymer-element>