Revert of Move JoinString to the base namespace

chrome/browser/net/safe_search_util.cc

 // Copyright 2014 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 "chrome/browser/net/safe_search_util.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 45 matching lines @@
   std::vector<std::string>::iterator it;
   for (it = parameters.begin(); it < parameters.end(); ++it) {
     if (!HasSameParameterKey(*it, safe_parameter) &&
         !HasSameParameterKey(*it, ssui_parameter)) {
       new_parameters.push_back(*it);
     }
   }
 
   new_parameters.push_back(safe_parameter);
   new_parameters.push_back(ssui_parameter);
-  return base::JoinString(new_parameters, "&");
+  return JoinString(new_parameters, '&');
 }
 
 } // namespace
 
 namespace safe_search_util {
 
 // If |request| is a request to Google Web Search the function
 // enforces that the SafeSearch query parameters are set to active.
 // Sets the query part of |new_url| with the new value of the parameters.
 void ForceGoogleSafeSearch(const net::URLRequest* request, GURL* new_url) {
@@ skipping 39 matching lines @@
 
 void ClearForceGoogleSafeSearchCountForTesting() {
   g_force_google_safe_search_count_for_test = 0;
 }
 
 void ClearForceYouTubeSafetyModeCountForTesting() {
   g_force_youtube_safety_mode_count_for_test = 0;
 }
 
 }  // namespace safe_search_util