Settings: Network: Merge Tether networks into Mobile subpage

chrome/browser/resources/settings/internet_page/network_summary.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 a summary of network states
  * by type: Ethernet, WiFi, Cellular, WiMAX, and VPN.
  */
 
 /**
@@ skipping 292 matching lines @@
     var newActiveNetworkStates = [];
     this.activeNetworkIds_ = new Set;
     var orderedDeviceTypes = [
       CrOnc.Type.ETHERNET, CrOnc.Type.WI_FI, CrOnc.Type.CELLULAR,
       CrOnc.Type.TETHER, CrOnc.Type.WI_MAX, CrOnc.Type.VPN
     ];
     for (var i = 0; i < orderedDeviceTypes.length; ++i) {
       var type = orderedDeviceTypes[i];
       var device = newDeviceStates[type];
       if (!device)
+        continue;  // The technology for this device type is unavailable.
+
+      // If both 'Tether' and 'Cellular' technoligies exist, merge the network
+      // lists and do not add an active network for 'Tether' so that there is
+      // only one 'Mobile data' section / subpage.
+      if (type == CrOnc.Type.TETHER && newDeviceStates[CrOnc.Type.CELLULAR]) {
+        newNetworkStateLists[CrOnc.Type.CELLULAR] =
+            newNetworkStateLists[CrOnc.Type.CELLULAR].concat(
+                newNetworkStateLists[CrOnc.Type.TETHER]);
         continue;
-      var state = activeNetworkStatesByType.get(type) || {GUID: '', Type: type};
+      }
+
+      // Note: The active state for 'Cellular' may be a Tether network if both
+      // types are enabled but no Cellular network exists (edge case).
+      var state = this.getActiveStateForType_(activeNetworkStatesByType, type);
       if (state.Source === undefined &&
           device.State == CrOnc.DeviceState.PROHIBITED) {
         // Prohibited technologies are enforced by the device policy.
         state.Source = CrOnc.Source.DEVICE_POLICY;
       }
       newActiveNetworkStates.push(state);
       this.activeNetworkIds_.add(state.GUID);
     }
 
     this.deviceStates = newDeviceStates;
     this.networkStateLists_ = newNetworkStateLists;
     // Set activeNetworkStates last to rebuild the dom-repeat.
     this.activeNetworkStates_ = newActiveNetworkStates;
   },
+
+  /**
+   * Returns the active network state for |type| or a default network state.
+   * If there is no 'Cellular' network, return the active 'Tether' network if
+   * any since the two types are represented by the same section / subpage.
+   * @param {!Map<string, !CrOnc.NetworkStateProperties>} activeStatesByType
+   * @param {string} type
+   * @return {!CrOnc.NetworkStateProperties|undefined}
+   */
+  getActiveStateForType_: function(activeStatesByType, type) {
+    var activeState = activeStatesByType.get(type);
+    if (!activeState && type == CrOnc.Type.CELLULAR)
+      activeState = activeStatesByType.get(CrOnc.Type.TETHER);
+    return activeState || {GUID: '', Type: type};
+  },
 });