Remove v1 of Startup.FirstWebContents.* stats deprecated in M48.

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 2b2885f61a9141bbad9ecf0bacc1b6c98ee5e281..df70daf07a7ccc3f36a5ab2056fd4b089788b19f 100644
--- a/components/startup_metric_utils/browser/startup_metric_utils.h
+++ b/components/startup_metric_utils/browser/startup_metric_utils.h
@@ -76,20 +76,10 @@ void RecordBrowserOpenTabsDelta(const base::TimeDelta& delta);
 // only if the first web contents was unimpended in its attempt to do so.
 void RecordFirstWebContentsMainFrameLoad(const base::TimeTicks& ticks);
 
-// Call this with the time when the first web contents loaded its main frame.
-// This records an old stat kept for comparison purposes until M49.
-void RecordDeprecatedFirstWebContentsMainFrameLoad(
-    const base::TimeTicks& ticks);
-
 // Call this with the time when the first web contents had a non-empty paint,
 // only if the first web contents was unimpended in its attempt to do so.
 void RecordFirstWebContentsNonEmptyPaint(const base::TimeTicks& ticks);
 
-// Call this with the time when the first web contents had a non-empty paint.
-// This records an old stat kept for comparison purposes until M49.
-void RecordDeprecatedFirstWebContentsNonEmptyPaint(
-    const base::TimeTicks& ticks);
-
 // Call this with the time when the first web contents began navigating its main
 // frame.
 void RecordFirstWebContentsMainNavigationStart(const base::TimeTicks& ticks);