Buffer cross frame paint timing updates.

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 ac5c21b4d239baef2b05c47e49f607a7cce58ec3..27bc8c84229ab173821d3871c62cbeb0e55c2888 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.h
@@ -97,6 +97,7 @@ class MetricsWebContentsObserver
   void MediaStartedPlaying(
       const content::WebContentsObserver::MediaPlayerInfo& video_type,
       const content::WebContentsObserver::MediaPlayerId& id) override;
+  void WebContentsDestroyed() override;
 
   // These methods are forwarded from the MetricsNavigationThrottle.
   void WillStartNavigationRequest(content::NavigationHandle* navigation_handle);