Makes Screen functions take a const gfx::NativeView

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 127 matching lines @@
     NOTIMPLEMENTED();
     return gfx::NativeWindow();
   }
 
   int GetNumDisplays() const override { return GetAllDisplays().size(); }
 
   std::vector<Display> GetAllDisplays() const override {
     return displays_;
   }
 
-  Display GetDisplayNearestWindow(gfx::NativeView view) const override {
+  Display GetDisplayNearestWindow(const gfx::NativeView view) const override {
     NSWindow* window = nil;
 #if !defined(USE_AURA)
     if (view)
       window = [view window];
 #endif
     if (!window)
       return GetPrimaryDisplay();
     NSScreen* match_screen = [window screen];
     if (!match_screen)
       return GetPrimaryDisplay();
@@ skipping 139 matching lines @@
 
 }  // namespace
 
 #if !defined(USE_AURA)
 Screen* CreateNativeScreen() {
   return new ScreenMac;
 }
 #endif
 
 }  // namespace display