[CrOS Tether] Add tether settings section to the MD settings page.

ui/webui/resources/cr_elements/network/cr_network_icon.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 rendering network icons based on ONC
  * state properties.
  */
 
 Polymer({
@@ skipping 25 matching lines @@
    */
   getIconClass_: function() {
     if (!this.networkState)
       return '';
     var type = this.networkState.Type;
     if (type == CrOnc.Type.ETHERNET)
       return 'ethernet';
     if (type == CrOnc.Type.VPN)
       return 'vpn';
 
-    var prefix = type == CrOnc.Type.CELLULAR ? 'cellular-' : 'wifi-';
+    var prefix = (type == CrOnc.Type.CELLULAR || type == CrOnc.Type.TETHER) ?
+        'cellular-' :
+        'wifi-';
     var connectionState = this.networkState.ConnectionState;
     if (connectionState == CrOnc.ConnectionState.CONNECTING)
       return prefix + 'connecting';
     var strength;
     if (!this.isListItem &&
         (!connectionState ||
          connectionState == CrOnc.ConnectionState.NOT_CONNECTED)) {
-      if (type != CrOnc.Type.CELLULAR)
+      if (type != CrOnc.Type.CELLULAR && type != CrOnc.Type.TETHER)
         return prefix + 'off';
       strength = 0;
     } else {
       strength = CrOnc.getSignalStrength(this.networkState);
     }
     return prefix + this.strengthToIndex_(strength).toString(10);
   },
 
   /**
    * @param {number} strength The signal strength from [0 - 100].
@@ skipping 75 matching lines @@
     if (networkState.Type != CrOnc.Type.WI_FI || !networkState.WiFi)
       return false;
     if (!this.isListItem &&
         networkState.ConnectionState == CrOnc.ConnectionState.NOT_CONNECTED) {
       return false;
     }
     var security = networkState.WiFi.Security;
     return !!security && security != 'None';
   },
 });