Ensure the 1993 NTP logs to UMA Most Visited tiles that use the fallback thumbnail instead of the p…

chrome/browser/resources/local_ntp/most_visited_thumbnail.js

Index: chrome/browser/resources/local_ntp/most_visited_thumbnail.js
diff --git a/chrome/browser/resources/local_ntp/most_visited_thumbnail.js b/chrome/browser/resources/local_ntp/most_visited_thumbnail.js
index 8952d70afa0f96be8442e3e61b9c752d7e85d707..dd3f4fddf4e9bb2cde016784610a695ea3b12227 100644
--- a/chrome/browser/resources/local_ntp/most_visited_thumbnail.js
+++ b/chrome/browser/resources/local_ntp/most_visited_thumbnail.js
@@ -51,9 +51,11 @@ window.addEventListener('DOMContentLoaded', function() {
         // The first thumbnail's onerror function will swap the visibility of
         // the two thumbnails.
         image.onerror = function() {
+          logEvent(NTP_LOGGING_EVENT_TYPE.NTP_FALLBACK_THUMBNAIL_USED);
           image.style.visibility = 'hidden';
           image2.style.visibility = 'visible';
         };
+        logEvent(NTP_LOGGING_EVENT_TYPE.NTP_FALLBACK_THUMBNAIL_REQUESTED);
       } else {
         image.onerror = showDomainElement;
       }