Add start/finish navigation to startup metrics.

components/startup_metric_utils/startup_metric_utils.h

Index: components/startup_metric_utils/startup_metric_utils.h
diff --git a/components/startup_metric_utils/startup_metric_utils.h b/components/startup_metric_utils/startup_metric_utils.h
index f2d13264823b4ce59c314249bc73804c527cdc8c..54a66cac7f4d0d1ceeb42188bc9d296f704ca606 100644
--- a/components/startup_metric_utils/startup_metric_utils.h
+++ b/components/startup_metric_utils/startup_metric_utils.h
@@ -74,6 +74,18 @@ void RecordFirstWebContentsMainFrameLoad(const base::Time& time);
 // Call this with the time when the first web contents had a non-empty paint.
 void RecordFirstWebContentsNonEmptyPaint(const base::Time& time);
 
+// Call this with the time when the first web contents began navigating its main
+// frame.
+void RecordFirstWebContentsMainNavigationStart(const base::Time& time);
+
+// Call this with the time when the first web contents completed a navigation
+// for its main frame.
+void RecordFirstWebContentsMainNavigationFinishedFirst(const base::Time& time);
+
+// Call this with the time when the first web contents completed all navigations
+// for its main frame.
+void RecordFirstWebContentsMainNavigationFinishedAll(const base::Time& time);
+
 // Returns the time of main entry recorded from RecordMainEntryPointTime.
 // Returns a null Time if a value has not been recorded yet.
 // This method is expected to be called from the UI thread.