Use container::back() and container::pop_back() in ui/

ui/display/mac/screen_mac.mm

 // 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 "ui/display/screen.h"
 
 #import <ApplicationServices/ApplicationServices.h>
 #import <Cocoa/Cocoa.h>
 #include <stdint.h>
 
@@ skipping 217 matching lines @@
         // The primary display in a mirrored set will be counted, but those that
         // mirror it will not be.
         ScreenIdsToScreensMap::iterator foundScreen =
             screen_ids_to_screens.find(online_display);
         if (foundScreen != screen_ids_to_screens.end()) {
           displays.push_back(GetDisplayForScreen(foundScreen->second));
         }
       }
     }
 
-    if (!displays.size())
-      return std::vector<Display>(1, GetPrimaryDisplay());
-
-    return displays;
+    return displays.empty() ? std::vector<Display>(1, GetPrimaryDisplay())
+                            : displays;
   }
 
   // The displays currently attached to the device.
   std::vector<Display> displays_;
 
   // The timer to delay configuring outputs. See also the comments in
   // HandleDisplayReconfiguration().
   std::unique_ptr<base::OneShotTimer> configure_timer_;
 
   DisplayChangeNotifier change_notifier_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenMac);
 };
 
 }  // namespace
 
 #if !defined(USE_AURA)
 Screen* CreateNativeScreen() {
   return new ScreenMac;
 }
 #endif
 
 }  // namespace display