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

ui/webui/resources/cr_elements/network/cr_network_icon.js

Index: ui/webui/resources/cr_elements/network/cr_network_icon.js
diff --git a/ui/webui/resources/cr_elements/network/cr_network_icon.js b/ui/webui/resources/cr_elements/network/cr_network_icon.js
index b77d138c4ae04c0c985a5ea190402027e992af79..1fa2afb9ed5f12dcdc307996324c7e0cc37d4d2d 100644
--- a/ui/webui/resources/cr_elements/network/cr_network_icon.js
+++ b/ui/webui/resources/cr_elements/network/cr_network_icon.js
@@ -43,7 +43,9 @@ Polymer({
     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';
@@ -51,7 +53,7 @@ Polymer({
     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 {