Use a direct include of strings headers in chrome/browser/d*/.

chrome/browser/download/download_item_model_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/browser/download/download_item_model.h"
 
 #include <vector>
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
-#include "base/string16.h"
-#include "base/string_util.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/test/mock_download_item.h"
 #include "grit/generated_resources.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/text/bytes_formatting.h"
 #include "ui/gfx/font.h"
 
 using content::DownloadItem;
@@ skipping 371 matching lines @@
     EXPECT_CALL(item(), IsDangerous())
         .WillRepeatedly(Return(test_case.is_dangerous));
 
     EXPECT_EQ(test_case.expected_result,
               model().ShouldRemoveFromShelfWhenComplete())
         << "Test case: " << i;
     Mock::VerifyAndClearExpectations(&item());
     Mock::VerifyAndClearExpectations(&model());
   }
 }