bluetooth: When adding a device a second time merge the list of services.

content/browser/bluetooth/bluetooth_allowed_devices_map.h

 // 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.
 
 #ifndef CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_ALLOWED_DEVICES_MAP_
 #define CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_ALLOWED_DEVICES_MAP_
 
 #include <map>
 #include <set>
 #include <vector>
@@ skipping 50 matching lines @@
                                       const std::string& service_uuid) const;
 
  private:
   typedef std::map<std::string, std::string> DeviceAddressToIdMap;
   typedef std::map<std::string, std::string> DeviceIdToAddressMap;
   typedef std::map<std::string, std::set<std::string>> DeviceIdToServicesMap;
 
   // Returns an id guaranteed to be unique for the map. The id is randomly
   // generated so that an origin can't guess the id used in another origin.
   std::string GenerateDeviceId();
-  std::set<std::string> UnionOfServices(
+  void AddUnionOfServicesTo(
       const std::vector<BluetoothScanFilter>& filters,
-      const std::vector<device::BluetoothUUID>& optional_services);
+      const std::vector<device::BluetoothUUID>& optional_services,
+      std::set<std::string>* unionOfServices);
 
   std::map<url::Origin, DeviceAddressToIdMap>
       origin_to_device_address_to_id_map_;
   std::map<url::Origin, DeviceIdToAddressMap>
       origin_to_device_id_to_address_map_;
   std::map<url::Origin, DeviceIdToServicesMap>
       origin_to_device_id_to_services_map_;
 
   // Keep track of all device_ids in the map.
   std::set<std::string> device_id_set_;
 };
 
 }  //  namespace content
 
 #endif  // CONTENT_BROWSER_BLUETOOTH_BLUETOOTH_ALLOWED_DEVICES_MAP_