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

chrome/browser/safe_browsing/ping_manager.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/ping_manager.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
-#include "base/string_util.h"
-#include "base/stringprintf.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "chrome/common/env_vars.h"
 #include "content/public/browser/browser_thread.h"
 #include "google_apis/google_api_keys.h"
 #include "net/base/escape.h"
 #include "net/base/load_flags.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_context_getter.h"
 #include "net/url_request/url_request_status.h"
 
 using content::BrowserThread;
@@ skipping 127 matching lines @@
           url_prefix_.c_str(),
           client_name_.c_str(),
           version_.c_str());
   std::string api_key = google_apis::GetAPIKey();
   if (!api_key.empty()) {
     base::StringAppendF(&url, "&key=%s",
                         net::EscapeQueryParamValue(api_key, true).c_str());
   }
   return GURL(url);
 }