Use a valid /prefetch argument when launching a process.

chrome/browser/chrome_browser_main.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/browser/chrome_browser_main.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <set>
 #include <string>
@@ skipping 565 matching lines @@
   // Register a synthetic field trial with the PreRead group used during the
   // current startup. This must be done before the first metric log
   // (metrics::MetricLog) is created. Otherwise, UMA metrics generated during
   // startup won't be correctly annotated. The current function is always called
   // before the first metric log is created, as part of
   // ChromeBrowserMainParts::PreMainMessageLoopRun().
   startup_metric_utils::RegisterPreReadSyntheticFieldTrial(
       registry_path,
       base::Bind(&ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial));
 
-  // After startup is complete, update the pre-read group in the registry. The
+  // Initialize the PreRead options for the current process.
+  startup_metric_utils::InitializePreReadOptions(registry_path);
+
+  // After startup is complete, update the PreRead group in the registry. The
   // group written in the registry will be used for the next startup.
   BrowserThread::PostAfterStartupTask(
       FROM_HERE, content::BrowserThread::GetBlockingPool(),
       base::Bind(&startup_metric_utils::UpdatePreReadOptions, registry_path));
 }
 #endif  // defined(OS_WIN)
 
 // This error message is not localized because we failed to load the
 // localization data files.
 #if defined(OS_WIN)
@@ skipping 1277 matching lines @@
   chromeos::CrosSettings::Shutdown();
 #endif  // defined(OS_CHROMEOS)
 #endif  // defined(OS_ANDROID)
 }
 
 // Public members:
 
 void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
   chrome_extra_parts_.push_back(parts);
 }