Prefix string16 with base:: in ui/.

ui/views/controls/textfield/textfield_controller.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 "ui/views/controls/textfield/textfield_controller.h"
 
 #include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/events/event.h"
 
 namespace views {
@@ skipping 13 matching lines @@
 }
 
 bool TextfieldController::IsCommandIdEnabled(int command_id) const {
   return false;
 }
 
 bool TextfieldController::IsItemForCommandIdDynamic(int command_id) const {
   return false;
 }
 
-string16 TextfieldController::GetLabelForCommandId(int command_id) const {
-  return string16();
+base::string16 TextfieldController::GetLabelForCommandId(int command_id) const {
+  return base::string16();
 }
 
 bool TextfieldController::HandlesCommand(int command_id) const {
   return false;
 }
 
 }  // namespace views