Record first run startup metrics.

chrome/common/startup_metric_utils.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/common/startup_metric_utils.h"
 
 #include "base/hash_tables.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/metrics/histogram_base.h"
@@ skipping 47 matching lines @@
   g_main_entry_time_was_recorded = true;
   MainEntryPointTimeInternal();
 }
 
 // Return the time recorded by RecordMainEntryPointTime().
 const base::Time MainEntryStartTime() {
   DCHECK(g_main_entry_time_was_recorded);
   return *MainEntryPointTimeInternal();
 }
 
-void OnBrowserStartupComplete() {
+void OnBrowserStartupComplete(bool is_first_run) {
   // Bail if uptime < 7 minutes, to filter out cases where Chrome may have been
   // autostarted and the machine is under io pressure.
   const int64 kSevenMinutesInMilliseconds =
       base::TimeDelta::FromMinutes(7).InMilliseconds();
   if (base::SysInfo::Uptime() < kSevenMinutesInMilliseconds) {
     g_startup_stats_collection_finished = true;
     return;
   }
 
   // The Startup.BrowserMessageLoopStartTime histogram recorded in
   // chrome_browser_main.cc exhibits instability in the field which limits its
   // usefulness in all scenarios except when we have a very large sample size.
   // Attempt to mitigate this with a new metric:
   // * Measure time from main entry rather than the OS' notion of process start
   //   time.
   // * Only measure launches that occur 7 minutes after boot to try to avoid
   //   cases where Chrome is auto-started and IO is heavily loaded.
   base::TimeDelta startup_time_from_main_entry =
       base::Time::Now() - MainEntryStartTime();
   UMA_HISTOGRAM_LONG_TIMES(
-      "Startup.BrowserMessageLoopStartTimeFromMainEntry",
+      is_first_run ?
+          "Startup.FirstRun.BrowserMessageLoopStartTimeFromMainEntry" :
+          "Startup.BrowserMessageLoopStartTimeFromMainEntry",

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

Also split this into two explicit calls since these macros are meant to be used
with constant histogram values I think.

       startup_time_from_main_entry);
 
   // Create another histogram that records the exact number for use by
   // performance tests.
   int64 startup_time_from_main_entry_ms =
       startup_time_from_main_entry.InMilliseconds();
   HISTOGRAM_ENUMERATION(
-      "Startup.BrowserMessageLoopStartTimeFromMainEntry_Exact",
+      is_first_run ?
+          "Startup.FirstRun.BrowserMessageLoopStartTimeFromMainEntry_Exact" :

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

This histogram is only used for perf tests and is never sent to the server - I
don't think we need to add a new variant for first run...

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

Done.

+          "Startup.BrowserMessageLoopStartTimeFromMainEntry_Exact",
       startup_time_from_main_entry_ms,
       startup_time_from_main_entry_ms);
 
   // Record histograms for the subsystem times for startups > 10 seconds.
   const base::TimeDelta kTenSeconds = base::TimeDelta::FromSeconds(10);
   if (startup_time_from_main_entry < kTenSeconds) {
     g_startup_stats_collection_finished = true;
     return;
   }
 
@@ skipping 47 matching lines @@
   SubsystemStartupTimeHash* hash = GetSubsystemStartupTimeHash();
   // Only record the initial sample for a given histogram.
   if (hash->find(histogram_name_) !=  hash->end())
     return;
 
   (*hash)[histogram_name_] =
       base::TimeTicks::Now() - start_time_;
 }
 
 }  // namespace startup_metric_utils