MD Settings: Internet: Proxy: Support partial proxies

chrome/browser/resources/settings/internet_page/network_proxy_input.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview Polymer element for displaying and editing a single
  * network proxy value. When the URL or port changes, a 'proxy-change' event is
  * fired with the combined url and port values passed as a single string,
  * url:port.
  */
@@ skipping 28 matching lines @@
       },
       notify: true,
     },
   },
 
   /**
    * Event triggered when an input value changes.
    * @private
    */
   onValueChange_: function() {
-    if (!this.value.Host)
-      return;
     var port = parseInt(this.value.Port, 10);
     if (isNaN(port))
       port = 80;
     this.value.Port = port;
     this.fire('proxy-change', {value: this.value});
   }
 });