Prevent tracking metrics for cases such as 204s and downloads.

chrome/browser/page_load_metrics/page_load_metrics_observer.h

Index: chrome/browser/page_load_metrics/page_load_metrics_observer.h
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_observer.h b/chrome/browser/page_load_metrics/page_load_metrics_observer.h
index e60224022ff447bb3ef0663ca1fc912163b4c09b..c535146c86d7ae08b7da451d4afcbba9adffce72 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_observer.h
+++ b/chrome/browser/page_load_metrics/page_load_metrics_observer.h
@@ -254,9 +254,7 @@ class PageLoadMetricsObserver {
                           const PageLoadExtraInfo& extra_info) {}
 
   // OnFailedProvisionalLoad is invoked for tracked page loads that did not
-  // commit, immediately before the observer is deleted. Note that provisional
-  // loads that result in downloads or 204s are aborted by the system, and are
-  // also included as failed provisional loads.
+  // commit, immediately before the observer is deleted.
   virtual void OnFailedProvisionalLoad(
       const FailedProvisionalLoadInfo& failed_provisional_load_info,
       const PageLoadExtraInfo& extra_info) {}