Revert of Move JoinString to the base namespace

extensions/browser/api/management/management_api.cc

 // 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.
 
 #include "extensions/browser/api/management/management_api.h"
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 481 matching lines @@
 
 void ManagementSetEnabledFunction::OnRequirementsChecked(
     const std::vector<std::string>& requirements_errors) {
   if (requirements_errors.empty()) {
     ManagementAPI::GetFactoryInstance()->Get(browser_context())->GetDelegate()->
         EnableExtension(browser_context(), extension_id_);
     Respond(NoArguments());
   } else {
     // TODO(devlin): Should we really be noisy here all the time?
     Respond(Error(keys::kMissingRequirementsError,
-                  base::JoinString(requirements_errors, " ")));
+                  JoinString(requirements_errors, ' ')));
   }
 }
 
 ManagementUninstallFunctionBase::ManagementUninstallFunctionBase() {
 }
 
 ManagementUninstallFunctionBase::~ManagementUninstallFunctionBase() {
 }
 
 ExtensionFunction::ResponseAction ManagementUninstallFunctionBase::Uninstall(
@@ skipping 386 matching lines @@
 ManagementAPI::GetFactoryInstance() {
   return g_factory.Pointer();
 }
 
 void ManagementAPI::OnListenerAdded(const EventListenerInfo& details) {
   management_event_router_.reset(new ManagementEventRouter(browser_context_));
   EventRouter::Get(browser_context_)->UnregisterObserver(this);
 }
 
 }  // namespace extensions