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

chrome/browser/search/local_ntp_source.cc

 // Copyright 2013 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/search/local_ntp_source.h"
 
 #include "base/logging.h"
 #include "base/memory/ref_counted_memory.h"
-#include "base/string_util.h"
-#include "base/stringprintf.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/values.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
 #include "grit/browser_resources.h"
 #include "grit/generated_resources.h"
 #include "grit/ui_resources.h"
 #include "net/url_request/url_request.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/webui/jstemplate_builder.h"
@@ skipping 125 matching lines @@
   }
   return false;
 }
 
 std::string LocalNtpSource::GetContentSecurityPolicyFrameSrc() const {
   // Allow embedding of suggestion and most visited iframes.
   return base::StringPrintf("frame-src %s %s;",
                             chrome::kChromeSearchSuggestionUrl,
                             chrome::kChromeSearchMostVisitedUrl);
 }