Record first run startup metrics.

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index f89afc83cb5b365829edbb7613de8520c6c3bb29..33869cd6cdacc77d67b20c33f2686224d1849682 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -1623,7 +1623,7 @@ bool ChromeBrowserMainParts::MainMessageLoopRun(int* result_code) {
   // These should be invoked as close to the start of the browser's
   // UI thread message loop as possible to get a stable measurement
   // across versions.
-  RecordBrowserStartupTime();
+  RecordBrowserStartupTime(do_first_run_tasks_);
   startup_timer_->SignalStartupComplete(
       performance_monitor::StartupTimer::STARTUP_NORMAL);
 
@@ -1744,7 +1744,7 @@ void ChromeBrowserMainParts::AddParts(ChromeBrowserMainExtraParts* parts) {
 
 // Misc ------------------------------------------------------------------------
 
-void RecordBrowserStartupTime() {
+void RecordBrowserStartupTime(bool is_first_run) {
   // Don't record any metrics if UI was displayed before this point e.g.
   // warning dialogs.
   if (startup_metric_utils::WasNonBrowserUIDisplayed())
@@ -1756,13 +1756,16 @@ void RecordBrowserStartupTime() {
   const base::Time* process_creation_time =
       base::CurrentProcessInfo::CreationTime();
 
-  if (process_creation_time)
-    RecordPreReadExperimentTime("Startup.BrowserMessageLoopStartTime",
+  if (process_creation_time) {
+    RecordPreReadExperimentTime(
+        is_first_run ? "Startup.FirstRun.BrowserMessageLoopStartTime" :
+                       "Startup.BrowserMessageLoopStartTime",

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

I don't think you need to add a new histogram here, add one to the
"Startup.BrowserMessageLoopStartTimeFromMainEntry" instead.

LoopStartTime and LoopStartTimeFromMainEntry basically measure the same thing
(the former being the old version which is more noisy since it measures from the
OS' notion of process startup so we also measure binary load time)

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

Ok, let's not record this one on first run though then since that would add even
more noise to this stat.

         base::Time::Now() - *process_creation_time);
+  }
 #endif  // defined(OS_MACOSX) || defined(OS_WIN)
 
   // Record collected startup metrics.
-  startup_metric_utils::OnBrowserStartupComplete();
+  startup_metric_utils::OnBrowserStartupComplete(is_first_run);
 
   // Deletes self.
   new LoadCompleteListener();