Make PageLoadMetricsWaiter more resilient

chrome/browser/page_load_metrics/metrics_web_contents_observer.h

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.h
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
index 4f794b818a078c296bd08cc7c5a93a7189aaefc7..81b858b7a9e13e465fc7fe2b38b34a88846e8339 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
@@ -60,11 +60,7 @@ class MetricsWebContentsObserver
 
     void OnGoingAway();
 
-    // Invoked when a new PageLoadTiming update has been received and processed.
-    virtual void OnTimingUpdated(bool is_main_frame,
-                                 const mojom::PageLoadTiming& timing,
-                                 const mojom::PageLoadMetadata& metadata) {}
-
+    virtual void OnCommit(PageLoadTracker* tracker) {}
     virtual void DidReceiveTimingUpdate(IPCType type) {}
 
    private: