Use a direct include of strings headers in content/browser/, part 1.

content/browser/download/save_package_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 <string>
 
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/path_service.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/browser/download/save_package.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
 #include "content/test/net/url_request_mock_http_job.h"
 #include "content/test/test_web_contents.h"
 #include "googleurl/src/gurl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace content {
 
@@ skipping 410 matching lines @@
   GURL view_source_url = URLRequestMockHTTPJob::GetMockViewSourceUrl(
                              base::FilePath(kTestDir).Append(file_name));
   GURL actual_url = URLRequestMockHTTPJob::GetMockUrl(
                         base::FilePath(kTestDir).Append(file_name));
   NavigateAndCommit(view_source_url);
   EXPECT_EQ(actual_url, GetUrlToBeSaved());
   EXPECT_EQ(view_source_url, contents()->GetURL());
 }
 
 }  // namespace content