Use a valid /prefetch argument when launching a process.

chrome/installer/util/auto_launch_util.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/installer/util/auto_launch_util.h"
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/path_service.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/win/win_util.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/installer/util/util_constants.h"
+#include "components/startup_metric_utils/common/pre_read_field_trial_utils_win.h"
 #include "crypto/sha2.h"
 
 namespace {
 
 // The prefix of the Chrome Auto-launch key under the Run key.
 const wchar_t kAutolaunchKeyValue[] = L"GoogleChromeAutoLaunch";
 
 // Builds a registry key name to use when deciding where to read/write the auto-
 // launch value to/from. It takes into account the path of the profile so that
 // different installations of Chrome don't conflict.
@@ skipping 18 matching lines @@
 namespace auto_launch_util {
 
 void EnableBackgroundStartAtLogin() {
   base::FilePath application_dir;
   if (!PathService::Get(base::DIR_EXE, &application_dir))
     NOTREACHED();
 
   base::CommandLine cmd_line(application_dir.Append(installer::kChromeExe));
   cmd_line.AppendSwitch(switches::kNoStartupWindow);
 
+  if (startup_metric_utils::GetPreReadOptions().prefetch_argument)
+    cmd_line.AppendArg(switches::kPrefetchArgumentBrowserBackground);
+
   base::win::AddCommandToAutoRun(HKEY_CURRENT_USER, GetAutoLaunchKeyName(),
                                  cmd_line.GetCommandLineString());
 }
 
 void DisableBackgroundStartAtLogin() {
   base::win::RemoveCommandFromAutoRun(HKEY_CURRENT_USER,
                                       GetAutoLaunchKeyName());
 }
 
 }  // namespace auto_launch_util