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

content/browser/renderer_host/media/video_capture_controller.cc

 // 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.
 
 #include "content/browser/renderer_host/media/video_capture_controller.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <map>
@@ skipping 161 matching lines @@
            media::PIXEL_STORAGE_GPUMEMORYBUFFER)) {
     // Crash in debug builds since the renderer should not have asked for
     // invalid or unsupported parameters.
     LOG(DFATAL) << "Invalid or unsupported video capture parameters requested: "
                 << media::VideoCaptureFormat::ToString(params.requested_format);
     event_handler->OnError(id);
     return;
   }
 
   // If this is the first client added to the controller, cache the parameters.
-  if (!controller_clients_.size())
+  if (controller_clients_.empty())
     video_capture_format_ = params.requested_format;
 
   // Signal error in case device is already in error state.
   if (state_ == VIDEO_CAPTURE_STATE_ERROR) {
     event_handler->OnError(id);
     return;
   }
 
   // Do nothing if this client has called AddClient before.
   if (FindClient(id, event_handler, controller_clients_))
@@ skipping 314 matching lines @@
     int session_id,
     const ControllerClients& clients) {
   for (auto client : clients) {
     if (client->session_id == session_id)
       return client;
   }
   return NULL;
 }
 
 }  // namespace content