Use a direct include of strings headers in chrome_frame/.

chrome_frame/test/test_server_test.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 <windows.h>
 #include <wininet.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/path_service.h"
-#include "base/stringprintf.h"
+#include "base/strings/stringprintf.h"
 #include "base/win/scoped_handle.h"
 #include "chrome_frame/test/test_server.h"
 #include "net/cookies/cookie_monster.h"
 #include "net/disk_cache/disk_cache.h"
 #include "net/dns/host_resolver_proc.h"
 #include "net/http/http_auth_handler_factory.h"
 #include "net/http/http_cache.h"
 #include "net/http/http_network_session.h"
 #include "net/proxy/proxy_service.h"
 #include "net/url_request/url_request.h"
@@ skipping 165 matching lines @@
     EXPECT_EQ(file.accessed(), 1);
     EXPECT_EQ(redir.accessed(), 1);
 
     EXPECT_TRUE(person_task.response().find("Guthrie") != std::string::npos);
     EXPECT_TRUE(file_task.response().find("function") != std::string::npos);
     EXPECT_TRUE(redir_task.response().find("Destination") != std::string::npos);
   } else {
     ::TerminateThread(worker, ~0);
   }
 }