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

base/i18n/icu_encoding_detection.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 BASE_I18N_ICU_ENCODING_DETECTION_H_
 #define BASE_I18N_ICU_ENCODING_DETECTION_H_
-#pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/i18n/base_i18n_export.h"
 
 namespace base {
 
 // Detect encoding of |text| and put the name of encoding (as returned by ICU)
 // in |encoding|. For ASCII texts |encoding| will be set to an empty string.
 // Returns true on success.
 BASE_I18N_EXPORT bool DetectEncoding(const std::string& text,
                                      std::string* encoding);
 
 // Detect all possible encodings of |text| and put their names
 // (as returned by ICU) in |encodings|. Returns true on success.
 // Note: this function may return encodings that may fail to decode |text|,
 // the caller is responsible for handling that.
 BASE_I18N_EXPORT bool DetectAllEncodings(const std::string& text,
                                          std::vector<std::string>* encodings);
 
 }  // namespace base
 
 #endif  // BASE_I18N_ICU_ENCODING_DETECTION_H_