Use a direct include of strings headers in base/.

base/metrics/field_trial.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/metrics/field_trial.h"
 
 #include "base/build_time.h"
 #include "base/logging.h"
 #include "base/rand_util.h"
 #include "base/sha1.h"
-#include "base/string_util.h"
-#include "base/stringprintf.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/sys_byteorder.h"
 
 namespace base {
 
 namespace {
 
 // Created a time value based on |year|, |month| and |day_of_month| parameters.
 Time CreateTimeFromParams(int year, int month, int day_of_month) {
   DCHECK_GT(year, 1970);
@@ skipping 466 matching lines @@
     used_without_global_ = true;
     return;
   }
   AutoLock auto_lock(global_->lock_);
   DCHECK(!global_->PreLockedFind(trial->trial_name()));
   trial->AddRef();
   global_->registered_[trial->trial_name()] = trial;
 }
 
 }  // namespace base