Make a pre-read A/B field-trial

chrome/browser/browser_main.h

 // 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.
 
 #ifndef CHROME_BROWSER_BROWSER_MAIN_H_
 #define CHROME_BROWSER_BROWSER_MAIN_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/gtest_prod_util.h"
@@ skipping 187 matching lines @@
 void RecordBreakpadStatusUMA(MetricsService* metrics);
 
 // Displays a warning message if some minimum level of OS support is not
 // present on the current platform.
 void WarnAboutMinimumSystemRequirements();
 
 // Records the time from our process' startup to the present time in
 // the UMA histogram |metric_name|.
 void RecordBrowserStartupTime();
 
+// Records a Startup category value to an UMA histogram in the context of the
+// PreReadExperiment field-trial. This will also report to the appropriate
+// Startup.HistogramName_PreRead(Enabled|Disabled) histogram as appropriate.
+// This is only called from OS_WIN specific code, so the implementation is
+// in browser_main_win.cc. This is a Windows specific experiment.
+void RecordPreReadExperimentTime(const char* name, base::TimeDelta time);
+
 #endif  // CHROME_BROWSER_BROWSER_MAIN_H_