Use a direct include of strings headers in chrome/browser/r*-s*/.

chrome/browser/safe_browsing/client_side_detection_service.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/safe_browsing/client_side_detection_service.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
 #include "base/stl_util.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/time.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/safe_browsing/client_model.pb.h"
 #include "chrome/common/safe_browsing/csd.pb.h"
 #include "chrome/common/safe_browsing/safebrowsing_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
@@ skipping 660 matching lines @@
     const std::string& report_url) {
   std::string url = report_url;
   std::string api_key = google_apis::GetAPIKey();
   if (!api_key.empty()) {
     base::StringAppendF(&url, "?key=%s",
                         net::EscapeQueryParamValue(api_key, true).c_str());
   }
   return url;
 }
 }  // namespace safe_browsing