ui: Pass display size by const reference in AddVirtualDisplay

ui/display/chromeos/display_configurator.h

 // Copyright 2014 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 UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_
 #define UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 258 matching lines @@
   // Checks the available color profiles for |display_id| and fills the result
   // into |profiles|.
   std::vector<ui::ColorCalibrationProfile> GetAvailableColorCalibrationProfiles(
       int64_t display_id);
 
   // Updates the color calibration to |new_profile|.
   bool SetColorCalibrationProfile(int64_t display_id,
                                   ui::ColorCalibrationProfile new_profile);
 
   // Enables/disables virtual display.
-  int64_t AddVirtualDisplay(gfx::Size display_size);
+  int64_t AddVirtualDisplay(const gfx::Size& display_size);
   bool RemoveVirtualDisplay(int64_t display_id);
 
   // Returns true if there is at least one display on.
   bool IsDisplayOn() const;
 
   void set_configure_display(bool configure_display) {
     configure_display_ = configure_display;
   }
 
   // Sets the gamma, degamma and correction matrix for |display_id| to the
@@ skipping 174 matching lines @@
 
   // This must be the last variable.
   base::WeakPtrFactory<DisplayConfigurator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayConfigurator);
 };
 
 }  // namespace ui
 
 #endif  // UI_DISPLAY_CHROMEOS_DISPLAY_CONFIGURATOR_H_