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 60ace4ec730cebd9f684c9790857f4e03fdb6e91..ac5c21b4d239baef2b05c47e49f607a7cce58ec3 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: