Record first run startup metrics.

chrome/common/startup_metric_utils.cc

Index: chrome/common/startup_metric_utils.cc
diff --git a/chrome/common/startup_metric_utils.cc b/chrome/common/startup_metric_utils.cc
index 6b12be5f51ab7b5d877371f54d9573abb491ace8..203d84b25a35a4ad9c930c4df9775fad3ffdae76 100644
--- a/chrome/common/startup_metric_utils.cc
+++ b/chrome/common/startup_metric_utils.cc
@@ -65,7 +65,7 @@ const base::Time MainEntryStartTime() {
   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 =
@@ -85,9 +85,15 @@ void OnBrowserStartupComplete() {
   //   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",
-      startup_time_from_main_entry);
+  if (is_first_run) {
+    UMA_HISTOGRAM_LONG_TIMES(
+        "Startup.BrowserMessageLoopStartTimeFromMainEntry.FirstRun",
+        startup_time_from_main_entry);
+  } else {
+    UMA_HISTOGRAM_LONG_TIMES(
+        "Startup.BrowserMessageLoopStartTimeFromMainEntry",
+        startup_time_from_main_entry);
+  }
 
   // Create another histogram that records the exact number for use by
   // performance tests.