Use a valid /prefetch argument when launching a process.

chrome/browser/browser_process_impl.cc

Index: chrome/browser/browser_process_impl.cc
diff --git a/chrome/browser/browser_process_impl.cc b/chrome/browser/browser_process_impl.cc
index cef743b78a93623124c2733222cebdb3621b3026..005f950374b6ee6888864fcea294a8644fdb82b8 100644
--- a/chrome/browser/browser_process_impl.cc
+++ b/chrome/browser/browser_process_impl.cc
@@ -111,6 +111,7 @@
 
 #if defined(OS_WIN)
 #include "base/win/windows_version.h"
+#include "components/startup_metric_utils/common/pre_read_field_trial_utils_win.h"
 #include "ui/views/focus/view_storage.h"
 #elif defined(OS_MACOSX)
 #include "chrome/browser/chrome_browser_main_mac.h"
@@ -1268,6 +1269,11 @@ void BrowserProcessImpl::RestartBackgroundInstance() {
       new_cl->AppendSwitch(kSwitchesToAddOnAutorestart[i]);
   }
 
+#if defined(OS_WIN)
+  if (startup_metric_utils::GetPreReadOptions().use_prefetch_argument)
+    new_cl->AppendArg(switches::kPrefetchArgumentBrowserBackground);
+#endif  // defined(OS_WIN)
+
   DLOG(WARNING) << "Shutting down current instance of the browser.";
   chrome::AttemptExit();