Add SameVersionStartupCounts suffix to startup HardFault and Temperature histograms.

components/startup_metric_utils/browser/startup_metric_utils.h

Index: components/startup_metric_utils/browser/startup_metric_utils.h
diff --git a/components/startup_metric_utils/browser/startup_metric_utils.h b/components/startup_metric_utils/browser/startup_metric_utils.h
index ba6c9cfff144d2821ab243df2956f570b2ef5268..410bf0a8ba5168a47e7c2be97c492143305fee2c 100644
--- a/components/startup_metric_utils/browser/startup_metric_utils.h
+++ b/components/startup_metric_utils/browser/startup_metric_utils.h
@@ -34,8 +34,8 @@ enum StartupTemperature {
   // The startup type couldn't quite be classified as warm or cold, but rather
   // was somewhere in between.
   LUKEWARM_STARTUP_TEMPERATURE = 2,
-  // This must be after all meaningful values.
-  STARTUP_TEMPERATURE_COUNT,
+  // This must be after all meaningful values and be equal to the last one.
+  STARTUP_TEMPERATURE_MAX = LUKEWARM_STARTUP_TEMPERATURE,
   // Startup temperature wasn't yet determined.
   UNDETERMINED_STARTUP_TEMPERATURE

[msw, 2016/01/26 18:08:30]

nit: trailing comma

[gab, 2016/01/26 18:15:07]

This is on purpose, this one should always be last, new ones should go above
STARTUP_TEMPERATURE_MAX. I can add a comment if you don't think this is clear.

[msw, 2016/01/26 18:16:51]

Acknowledged.

 };
@@ -76,21 +76,13 @@ void RecordMainEntryPointTime(const base::Time& time);
 void RecordExeMainEntryPointTime(const base::Time& time);
 
 // Call this with the time recorded just before the message loop is started.
-// |is_first_run| - is the current launch part of a first run.
+// |is_first_run| - is the current launch part of a first run. |pref_service| is
+// an optional parameter which, if provided, will be used to store state for
+// stats that span multiple startups; in its absence those stats will not be

[msw, 2016/01/26 18:08:30]

nit: maybe describe which stats, like the removed function comments?

[gab, 2016/01/26 18:15:07]

This is constantly subject to change so I intentionally left it vague as I think
it's wrong for the API to constantly be updated when metrics are added/removed.
All the caller needs to know is that : if you don't provide this param you're
missing out on all stats that span multiple startups but still getting the stats
specific to the current startup.

[msw, 2016/01/26 18:16:51]

Acknowledged.

+// recorded.
 void RecordBrowserMainMessageLoopStart(const base::TimeTicks& ticks,
-                                       bool is_first_run);
-
-// Logs the Startup.TimeSinceLastStartup histogram. Obtains the timestamp of the
-// last startup from |pref_service| and overwrites it with the timestamp of the
-// current startup. If the startup temperature has been set by
-// RecordBrowserMainMessageLoopStart, the time since last startup is also logged
-// to an histogram suffixed with the startup temperature.
-void RecordTimeSinceLastStartup(PrefService* pref_service);
-
-// Logs the Startup.SameVersionStartupCount histogram. Relies on |pref_service|
-// to know information about the previous startups and store information for
-// future ones.
-void RecordStartupCount(PrefService* pref_service);
+                                       bool is_first_run,
+                                       PrefService* pref_service);
 
 // Call this with the time when the first browser window became visible.
 void RecordBrowserWindowDisplay(const base::TimeTicks& ticks);