Add .SingleTab and .MultiTabs suffix to Startup.FirstWebContents.MainNavigationStart histogram.

components/startup_metric_utils/browser/startup_metric_utils.cc

Index: components/startup_metric_utils/browser/startup_metric_utils.cc
diff --git a/components/startup_metric_utils/browser/startup_metric_utils.cc b/components/startup_metric_utils/browser/startup_metric_utils.cc
index d45b768c291c959c685470ab56fd2011ec5f76bd..f1ad613d5df94bc95887beaafc255f963664c4c6 100644
--- a/components/startup_metric_utils/browser/startup_metric_utils.cc
+++ b/components/startup_metric_utils/browser/startup_metric_utils.cc
@@ -720,7 +720,8 @@ void RecordFirstWebContentsNonEmptyPaint(const base::TimeTicks& ticks) {
       g_process_creation_ticks.Get(), ticks);
 }
 
-void RecordFirstWebContentsMainNavigationStart(const base::TimeTicks& ticks) {
+void RecordFirstWebContentsMainNavigationStart(const base::TimeTicks& ticks,
+                                               WebContentsWorkload workload) {
   static bool is_first_call = true;
   if (!is_first_call || ticks.is_null())
     return;
@@ -734,6 +735,21 @@ void RecordFirstWebContentsMainNavigationStart(const base::TimeTicks& ticks) {
       UMA_HISTOGRAM_LONG_TIMES_100,
       "Startup.FirstWebContents.MainNavigationStart",
       g_process_creation_ticks.Get(), ticks);
+
+  // Log extra information about this startup's workload. Only added to this
+  // histogram as this extra suffix can help making it less noisy but isn't
+  // worth tripling the number of startup histograms either.
+  if (workload == WebContentsWorkload::SINGLE_TAB) {
+    UMA_HISTOGRAM_WITH_TEMPERATURE(
+        UMA_HISTOGRAM_LONG_TIMES_100,
+        "Startup.FirstWebContents.MainNavigationStart.SingleTab",
+        ticks - g_process_creation_ticks.Get());
+  } else {
+    UMA_HISTOGRAM_WITH_TEMPERATURE(
+        UMA_HISTOGRAM_LONG_TIMES_100,
+        "Startup.FirstWebContents.MainNavigationStart.MultiTabs",
+        ticks - g_process_creation_ticks.Get());
+  }
 }
 
 void RecordFirstWebContentsMainNavigationFinished(