Finishing: https://codereview.chromium.org/1948763003

device/bluetooth/bluetooth_low_energy_device_mac.mm

 // 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.
 
 #include "device/bluetooth/bluetooth_low_energy_device_mac.h"
 
 #import <CoreFoundation/CoreFoundation.h>
 #include <stddef.h>
 
 #include "base/mac/mac_util.h"
@@ skipping 304 matching lines @@
         static_cast<BluetoothRemoteGattServiceMac*>(gatt_service);
     if (gatt_service_mac->GetService() == cb_service)
       return gatt_service_mac;
   }
   return nullptr;
 }
 
 void BluetoothLowEnergyDeviceMac::DidDisconnectPeripheral(
     BluetoothDevice::ConnectErrorCode error_code) {
   SetGattServicesDiscoveryComplete(false);
-  // Explicitly take and erase GATT services one by one to ensure that calling
-  // GetGattService on removed service in GattServiceRemoved returns null.
-  std::vector<std::string> service_keys;
-  for (const auto& gatt_service : gatt_services_) {
-    service_keys.push_back(gatt_service.first);
-  }
-  for (const auto& key : service_keys) {
-    gatt_services_.take_and_erase(key);
-  }
+  // Removing all services at once to ensure that calling GetGattService on
+  // removed service in GattServiceRemoved returns null.
+  GattServiceMap gatt_services_swapped;
+  gatt_services_swapped.swap(gatt_services_);
+  gatt_services_swapped.clear();
   if (create_gatt_connection_error_callbacks_.empty()) {
     // TODO(http://crbug.com/585897): Need to pass the error.
     DidDisconnectGatt();
   } else {
     DidFailToConnectGatt(error_code);
   }
 }