ui: Pass display size by const reference in AddVirtualDisplay

ui/display/chromeos/display_configurator.cc

 // 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.
 
 #include "ui/display/chromeos/display_configurator.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 1098 matching lines @@
         Observer, observers_, OnDisplayModeChangeFailed(cached_displays_,
                                                         attempted_state));
   }
 }
 
 void DisplayConfigurator::NotifyPowerStateObservers() {
   FOR_EACH_OBSERVER(
       Observer, observers_, OnPowerStateChanged(current_power_state_));
 }
 
-int64_t DisplayConfigurator::AddVirtualDisplay(gfx::Size display_size) {
+int64_t DisplayConfigurator::AddVirtualDisplay(const gfx::Size& display_size) {
   if (last_virtual_display_id_ == 0xff) {
     LOG(WARNING) << "Exceeded virtual display id limit";
     return display::Display::kInvalidDisplayID;
   }
 
   DisplaySnapshotVirtual* virtual_snapshot =
       new DisplaySnapshotVirtual(GenerateDisplayID(kReservedManufacturerID, 0x0,
                                                    ++last_virtual_display_id_),
                                  display_size);
   virtual_display_snapshots_.push_back(virtual_snapshot);
@@ skipping 23 matching lines @@
   last_virtual_display_id_ = max_display_id & 0xff;
 
   return true;
 }
 
 bool DisplayConfigurator::IsDisplayOn() const {
   return current_power_state_ != chromeos::DISPLAY_POWER_ALL_OFF;
 }
 
 }  // namespace ui