Remove #pragma once. Just from base/ for now.

base/nix/xdg_util.h

 // 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.
 
 #ifndef BASE_NIX_XDG_UTIL_H_
 #define BASE_NIX_XDG_UTIL_H_
-#pragma once
 
 // XDG refers to http://en.wikipedia.org/wiki/Freedesktop.org .
 // This file contains utilities found across free desktop environments.
 //
 // TODO(brettw) this file should be in app/x11, but is currently used by
 // net. We should have a net API to allow the embedder to specify the behavior
 // that it uses XDG for, and then move this file.
 
 #include "base/base_export.h"
 
@@ skipping 48 matching lines @@
 // Return a string representation of the given desktop environment.
 // May return NULL in the case of DESKTOP_ENVIRONMENT_OTHER.
 BASE_EXPORT const char* GetDesktopEnvironmentName(DesktopEnvironment env);
 // Convenience wrapper that calls GetDesktopEnvironment() first.
 BASE_EXPORT const char* GetDesktopEnvironmentName(Environment* env);
 
 }  // namespace nix
 }  // namespace base
 
 #endif  // BASE_NIX_XDG_UTIL_H_