Change getDevices to use a DeviceCallback.

chrome/renderer/resources/extensions/experimental.bluetooth_custom_bindings.js

 // Copyright (c) 2012 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.
 
 // Custom bindings for the Bluetooth API.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var sendRequest = require('sendRequest').sendRequest;
-var lastError = require('last_error');
+var lastError = require('lastError');
 
 // Use custom bindings to create an undocumented event listener that will
 // receive events about device discovery and call the event listener that was
 // provided with the request to begin discovery.
 chromeHidden.registerCustomHook('experimental.bluetooth', function(api) {
   var apiFunctions = api.apiFunctions;
 
   chromeHidden.bluetooth = {};
+
+  function callCallbackIfPresent(args) {
+    if (typeof(args[args.length-1]) == "function") {
+      args[args.length-1]();
+    }
+  }
+
   chromeHidden.bluetooth.deviceDiscoveredHandler = null;
   chromeHidden.bluetooth.onDeviceDiscovered =
       new chrome.Event("experimental.bluetooth.onDeviceDiscovered");
-
   function clearDeviceDiscoveredHandler() {
     chromeHidden.bluetooth.onDeviceDiscovered.removeListener(
         chromeHidden.bluetooth.deviceDiscoveredHandler);
     chromeHidden.bluetooth.deviceDiscoveredHandler = null;
   }
-
   apiFunctions.setHandleRequest('startDiscovery',
       function() {
         var args = arguments;
         if (args.length > 0 && args[0] && args[0].deviceCallback) {
+          if (chromeHidden.bluetooth.deviceDiscoveredHandler != null) {
+            lastError.set("Concurrent discovery is not allowed.");
+            callCallbackIfPresent(args);
+            return;
+          }
+
           chromeHidden.bluetooth.deviceDiscoveredHandler =
               args[0].deviceCallback;
           chromeHidden.bluetooth.onDeviceDiscovered.addListener(
               chromeHidden.bluetooth.deviceDiscoveredHandler);
           sendRequest(this.name,
                       args,
                       this.definition.parameters,
                       {customCallback:this.customCallback});
         } else {
-          if (typeof(args[args.length-1]) == "function") {
-            var callback = args[args.length-1];
-            lastError.set("deviceCallback is required in the options object");
-            callback();
-            return;
-          }
+          lastError.set("deviceCallback is required in the options object");
+          callCallbackIfPresent(args);
         }
       });
   apiFunctions.setCustomCallback('startDiscovery',
       function(name, request, response) {
         if (chrome.runtime.lastError) {
           clearDeviceDiscoveredHandler();
           return;
         }
       });
   apiFunctions.setHandleRequest('stopDiscovery',
       function() {
         clearDeviceDiscoveredHandler();
         sendRequest(this.name, arguments, this.definition.parameters);
       });
+
+  chromeHidden.bluetooth.deviceSearchResultHandler = null;
+  chromeHidden.bluetooth.onDeviceSearchResult =
+      new chrome.Event("experimental.bluetooth.onDeviceSearchResult");
+  apiFunctions.setHandleRequest('getDevices',
+      function() {
+        var args = arguments;
+        if (args.length > 0 && args[0] && args[0].deviceCallback) {
+          if (chromeHidden.bluetooth.deviceSearchResultHandler != null) {
+            lastError.set("Concurrent calls to getDevices are not allowed.");
+            callCallbackIfPresent(args);
+            return;
+          }
+
+          chromeHidden.bluetooth.deviceSearchResultHandler =
+              args[0].deviceCallback;
+          chromeHidden.bluetooth.onDeviceSearchResult.addListener(
+              chromeHidden.bluetooth.deviceSearchResultHandler);
+          sendRequest(this.name,
+                      args,
+                      this.definition.parameters,
+                      {customCallback:this.customCallback});
+        } else {
+          lastError.set("deviceCallback is required in the options object");
+          callCallbackIfPresent(args);
+        }
+      });
+  apiFunctions.setCustomCallback('getDevices',
+      function(name, request, response) {
+        chromeHidden.bluetooth.onDeviceSearchResult.removeListener(
+            chromeHidden.bluetooth.deviceSearchResultHandler);
+        chromeHidden.bluetooth.deviceSearchResultHandler = null;
+      });
 });