Revert of Move JoinString to the base namespace

components/policy/core/browser/policy_error_map.cc

 // Copyright 2013 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 "components/policy/core/browser/policy_error_map.h"
 
 #include <utility>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ skipping 168 matching lines @@
                               const std::string& message) {
   AddError(new SchemaValidatingPendingError(policy, error_path, message));
 }
 
 base::string16 PolicyErrorMap::GetErrors(const std::string& policy) {
   CheckReadyAndConvert();
   std::pair<const_iterator, const_iterator> range = map_.equal_range(policy);
   std::vector<base::string16> list;
   for (const_iterator it = range.first; it != range.second; ++it)
     list.push_back(it->second);
-  return base::JoinString(list, base::ASCIIToUTF16("\n"));
+  return JoinString(list, '\n');
 }
 
 bool PolicyErrorMap::empty() {
   CheckReadyAndConvert();
   return map_.empty();
 }
 
 size_t PolicyErrorMap::size() {
   CheckReadyAndConvert();
   return map_.size();
@@ skipping 29 matching lines @@
 
 void PolicyErrorMap::CheckReadyAndConvert() {
   DCHECK(IsReady());
   for (size_t i = 0; i < pending_.size(); ++i) {
     Convert(pending_[i]);
   }
   pending_.clear();
 }
 
 }  // namespace policy