Remove #pragma once from chrome/browser/extensions

chrome/browser/extensions/default_apps_trial.h

 // Copyright (c) 2011 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 CHROME_BROWSER_EXTENSIONS_DEFAULT_APPS_TRIAL_H_
 #define CHROME_BROWSER_EXTENSIONS_DEFAULT_APPS_TRIAL_H_
-#pragma once
 
 // Strings used with default apps field trial.  If the field trial is running
 // base::FieldTrialList::TrialExists(kDefaultAppsTrial_Name) returns true.
 //
 // The field trial consists of two groups of users: those that get default apps
 // installed in the NTP and those that don't.  The group_name() of the field
 // trial object is used to determine the group that the user belongs to.
 //
 // The field trial is setup in ChromeBrowserMainParts::DefaultAppsFieldTrial()
 // based on the user's brand code:
 //
 //   - brand ECDA gets default apps
 //   - brand ECDB does not get default apps
 //   - any other brand code get default apps, but they are not part of the
 //     trial
 
 extern const char kDefaultAppsTrialName[];
 extern const char kDefaultAppsTrialNoAppsGroup[];
 extern const char kDefaultAppsTrialWithAppsGroup[];
 
 #endif  // CHROME_BROWSER_EXTENSIONS_DEFAULT_APPS_TRIAL_H_