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 2646171ab4ef0a3018c8ccb80344bf64ca3e7dcd..4e1c556cb47174c64654c63e5bb9e224617b42e9 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) {}