iwyu: Include stringprintf.h where appropriate, part 2.

chrome/renderer/external_extension_uitest.cc

 // Copyright (c) 2011 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 "base/string_util.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/test/automation/tab_proxy.h"
 #include "chrome/test/ui/ui_layout_test.h"
 #include "chrome/test/ui_test_utils.h"
 #include "net/base/escape.h"
 #include "net/test/test_server.h"
 
@@ skipping 150 matching lines @@
 #if 0
   // Remove the calls to FinishIsSearchProviderInstalledTest above when
   // re-enabling this code.
 
   // Do the verification.
   for (size_t i = 0; i < arraysize(test_data); ++i) {
     FinishIsSearchProviderInstalledTest(test_data[i]);
   }
 #endif
 }