Update PageLoadTiming to use base::Optional

components/page_load_metrics/browser/page_load_metrics_util.h

Index: components/page_load_metrics/browser/page_load_metrics_util.h
diff --git a/components/page_load_metrics/browser/page_load_metrics_util.h b/components/page_load_metrics/browser/page_load_metrics_util.h
index 66dc3aa7119f2cfc5dbba22b6032092d94ce1a78..788c9fdd0a7f4a93093fbbbc124d2e7afb57d9cb 100644
--- a/components/page_load_metrics/browser/page_load_metrics_util.h
+++ b/components/page_load_metrics/browser/page_load_metrics_util.h
@@ -40,8 +40,8 @@ bool WasStartedInForegroundOptionalEventInForeground(
 // - Parse started and did not complete but the entire page load duration
 // happened in the foreground.
 // - Parse completed and happened entirely in the foreground.
-bool WasParseInForeground(base::TimeDelta parse_start,
-                          base::TimeDelta parse_stop,
+bool WasParseInForeground(const base::Optional<base::TimeDelta>& parse_start,
+                          const base::Optional<base::TimeDelta>& parse_stop,
                           const PageLoadExtraInfo& info);
 }  // namespace page_load_metrics