Add explicit base namespace to string16 users.

chrome/common/extensions/api/omnibox/omnibox_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 "chrome/common/extensions/api/omnibox/omnibox_handler.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
@@ skipping 16 matching lines @@
       extension->GetManifestData(manifest_keys::kOmnibox));
   return info ? info->keyword : base::EmptyString();
 }
 
 OmniboxHandler::OmniboxHandler() {
 }
 
 OmniboxHandler::~OmniboxHandler() {
 }
 
-bool OmniboxHandler::Parse(Extension* extension, string16* error) {
+bool OmniboxHandler::Parse(Extension* extension, base::string16* error) {
   scoped_ptr<OmniboxInfo> info(new OmniboxInfo);
   const base::DictionaryValue* dict = NULL;
   if (!extension->manifest()->GetDictionary(manifest_keys::kOmnibox,
                                             &dict) ||
       !dict->GetString(kKeyword, &info->keyword) ||
       info->keyword.empty()) {
     *error = ASCIIToUTF16(manifest_errors::kInvalidOmniboxKeyword);
     return false;
   }
   extension->SetManifestData(manifest_keys::kOmnibox, info.release());
   return true;
 }
 
 const std::vector<std::string> OmniboxHandler::Keys() const {
   return SingleKey(manifest_keys::kOmnibox);
 }
 
 }  // namespace extensions