bluetooth: Remove queuing of GetCharacteristicsCallbacks

chrome/browser/resources/bluetooth_internals/characteristic_list.js

 // Copyright 2017 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.
 
 /**
  * Javascript for CharacteristicList and CharacteristicListItem, served from
  *     chrome://bluetooth-internals/.
  */
 
 cr.define('characteristic_list', function() {
@@ skipping 164 matching lines @@
      */
     load: function(deviceAddress, serviceId) {
       if (this.characteristicsRequested_ || !this.isLoading())
         return;
 
       this.characteristicsRequested_ = true;
 
       device_broker.connectToDevice(deviceAddress).then(function(device) {
         return device.getCharacteristics(serviceId);
       }.bind(this)).then(function(response) {
-        this.setData(new ArrayDataModel(response.characteristics));
+        this.setData(new ArrayDataModel(response.characteristics || []));
         this.setLoading(false);
         this.characteristicsRequested_ = false;
       }.bind(this)).catch(function(error) {
         this.characteristicsRequested_ = false;
         Snackbar.show(
             deviceAddress + ': ' + error.message, SnackbarType.ERROR, 'Retry',
             function() {
               this.load(deviceAddress, serviceId);
             }.bind(this));
       }.bind(this));
     },
   };
 
   return {
     CharacteristicList: CharacteristicList,
     CharacteristicListItem: CharacteristicListItem,
   };
 });