Use a direct include of strings headers in base/.

base/process_linux.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/process.h"
 
 #include <errno.h>
 #include <sys/resource.h>
 
 #include "base/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
-#include "base/stringprintf.h"
 #include "base/strings/string_split.h"
+#include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 
 namespace {
 const int kForegroundPriority = 0;
 
 #if defined(OS_CHROMEOS)
 // We are more aggressive in our lowering of background process priority
 // for chromeos as we have much more control over other processes running
 // on the machine.
 //
@@ skipping 103 matching lines @@
   if (cgroups.Get().enabled)
     return true;
 #endif
 
   static LazyInstance<CheckForNicePermission> check_for_nice_permission =
       LAZY_INSTANCE_INITIALIZER;
   return check_for_nice_permission.Get().can_reraise_priority;
 }
 
 }  // namespace base