Use a direct include of strings headers in chrome/common/, part 1.

chrome/common/extensions/message_bundle_unittest.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/message_bundle.h"
 
 #include <string>
 #include <vector>
 
 #include "base/i18n/rtl.h"
 #include "base/memory/linked_ptr.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/common/extensions/extension_l10n_util.h"
 #include "chrome/common/extensions/extension_manifest_constants.h"
 #include "extensions/common/error_utils.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace errors = extension_manifest_errors;
 
 namespace extensions {
@@ skipping 396 matching lines @@
   messages.insert(std::make_pair("message_name", "message_value"));
   (*GetExtensionToL10nMessagesMap())[extension_id] = messages;
 
   L10nMessagesMap* map = GetL10nMessagesMap(extension_id);
   ASSERT_TRUE(NULL != map);
   EXPECT_EQ(1U, map->size());
   EXPECT_EQ("message_value", (*map)["message_name"]);
 }
 
 }  // namespace extensions