Use a direct include of strings headers in content/browser/, part 2.

content/browser/web_contents/navigation_controller_impl_unittest.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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/path_service.h"
 #include "base/stl_util.h"
-#include "base/string_util.h"
+#include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time.h"
 //  These are only used for commented out tests.  If someone wants to enable
 //  them, they should be moved to chrome first.
 //  #include "chrome/browser/history/history_service.h"
 //  #include "chrome/browser/profiles/profile_manager.h"
 //  #include "chrome/browser/sessions/session_service.h"
 //  #include "chrome/browser/sessions/session_service_factory.h"
 //  #include "chrome/browser/sessions/session_service_test_helper.h"
 //  #include "chrome/browser/sessions/session_types.h"
@@ skipping 3858 matching lines @@
                     PAGE_TRANSITION_LINK);
   session_helper_.AssertNavigationEquals(nav,
                                          windows_[0]->tabs[0]->navigations[0]);
   nav.set_url(url2);
   session_helper_.AssertNavigationEquals(nav,
                                          windows_[0]->tabs[0]->navigations[1]);
 }
 */
 
 }  // namespace content