Convert string16 to base::string16 in content.

content/browser/webui/web_ui_message_handler.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 "content/public/browser/web_ui_message_handler.h"
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
@@ skipping 18 matching lines @@
                                              double* out_value) {
   std::string string_value;
   if (value->GetString(0, &string_value))
     return base::StringToDouble(string_value, out_value);
   if (value->GetDouble(0, out_value))
     return true;
   NOTREACHED();
   return false;
 }
 
-string16 WebUIMessageHandler::ExtractStringValue(const ListValue* value) {
-  string16 string16_value;
+base::string16 WebUIMessageHandler::ExtractStringValue(const ListValue* value) {
+  base::string16 string16_value;
   if (value->GetString(0, &string16_value))
     return string16_value;
   NOTREACHED();
-  return string16();
+  return base::string16();
 }
 
 }  // namespace content