Record first run startup metrics.

chrome/browser/chrome_browser_main.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROME_BROWSER_MAIN_H_
 #define CHROME_BROWSER_CHROME_BROWSER_MAIN_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/field_trial.h"
@@ skipping 197 matching lines @@
 // sending crash reports.  The presence of a Breakpad handler (after
 // attempting to initialize crash reporting) and the presence of a debugger
 // are registered with the UMA metrics service.
 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 Startup.BrowserMessageLoopStartTime UMA histogram.
-void RecordBrowserStartupTime();
+// the Startup.BrowserMessageLoopStartTime UMA histogram (records
+// Startup.FirstRun.BrowserMessageLoopStartTime instead if |is_first_run|).

[jeremy, 2013/05/05 12:35:56]

2 histogram names seems confusing here, how about changing this comment to read:
Record time from process startup to present time in an UMA histogram.
|is_first_run| - is the current launch part of a first run.

[gab, 2013/05/06 16:19:54]

Done.

+void RecordBrowserStartupTime(bool is_first_run);
 
 // Records a time value to an UMA histogram in the context of the
 // PreReadExperiment field-trial. This also reports to the appropriate
 // sub-histogram (_PreRead(Enabled|Disabled)).
 void RecordPreReadExperimentTime(const char* name, base::TimeDelta time);
 
 #endif  // CHROME_BROWSER_CHROME_BROWSER_MAIN_H_