Always use a /prefetch:# switch when launching a process on Windows.

chrome/service/service_utility_process_host.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 "chrome/service/service_utility_process_host.h"
 
 #include <stdint.h>
 
 #include <queue>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/metrics/histogram.h"
 #include "base/process/launch.h"
 #include "base/task_runner_util.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/chrome_utility_printing_messages.h"
-#include "components/startup_metric_utils/common/pre_read_field_trial_utils_win.h"
 #include "content/public/common/child_process_host.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/result_codes.h"
 #include "content/public/common/sandbox_init.h"
 #include "content/public/common/sandboxed_process_launcher_delegate.h"
 #include "ipc/ipc_switches.h"
 #include "printing/emf_win.h"
 #include "sandbox/win/src/sandbox_policy.h"
 #include "sandbox/win/src/sandbox_types.h"
 #include "ui/base/ui_base_switches.h"
@@ skipping 182 matching lines @@
   base::FilePath exe_path = GetUtilityProcessCmd();
   if (exe_path.empty()) {
     NOTREACHED() << "Unable to get utility process binary name.";
     return false;
   }
 
   base::CommandLine cmd_line(exe_path);
   cmd_line.AppendSwitchASCII(switches::kProcessType, switches::kUtilityProcess);
   cmd_line.AppendSwitchASCII(switches::kProcessChannelID, channel_id);
   cmd_line.AppendSwitch(switches::kLang);
-
-  if (startup_metric_utils::GetPreReadOptions().use_prefetch_argument)
-    cmd_line.AppendArg(switches::kPrefetchArgumentOther);
+  cmd_line.AppendArg(switches::kPrefetchArgumentOther);
 
   if (Launch(&cmd_line, no_sandbox)) {
     ReportUmaEvent(SERVICE_UTILITY_STARTED);
     return true;
   }
   ReportUmaEvent(SERVICE_UTILITY_FAILED_TO_START);
   return false;
 }
 
 bool ServiceUtilityProcessHost::Launch(base::CommandLine* cmd_line,
@@ skipping 184 matching lines @@
     return false;
   }
   printing::Emf emf;
   if (!emf.InitFromData(data.data(), data.size())) {
     OnRenderPDFPagesToMetafileDone(false);
     return false;
   }
   OnRenderPDFPagesToMetafilePageDone(scale_factor, emf);
   return true;
 }