Use container::back() and container::pop_back().

device/bluetooth/bluez/bluetooth_socket_bluez.cc

 // Copyright 2013 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/bluez/bluetooth_socket_bluez.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <queue>
@@ skipping 381 matching lines @@
   VLOG(1) << profile_->object_path().value() << ": Request disconnection";
   callback.Run(SUCCESS);
 }
 
 void BluetoothSocketBlueZ::Cancel() {
   DCHECK(ui_task_runner()->RunsTasksOnCurrentThread());
   DCHECK(profile_);
 
   VLOG(1) << profile_->object_path().value() << ": Cancel";
 
-  if (!connection_request_queue_.size())
+  if (connection_request_queue_.empty())
     return;
 
   // If the front request is being accepted mark it as cancelled, otherwise
   // just pop it from the queue.
   linked_ptr<ConnectionRequest> request = connection_request_queue_.front();
   if (!request->accepting) {
     request->cancelled = true;
   } else {
     connection_request_queue_.pop();
   }
@@ skipping 122 matching lines @@
   DCHECK(profile_);
 
   VLOG(1) << profile_->object_path().value() << ": Release profile";
 
   static_cast<BluetoothAdapterBlueZ*>(adapter_.get())
       ->ReleaseProfile(device_path_, profile_);
   profile_ = nullptr;
 }
 
 }  // namespace bluez