Adding previews information to PLM UKM

chrome/browser/page_load_metrics/metrics_web_contents_observer.cc

Index: chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
diff --git a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
index 0cf731de80007c480ecb0dc922e710cc100d0793..5d24ffa3bd3c81109cf3824589807c9485cdc4fe 100644
--- a/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
+++ b/chrome/browser/page_load_metrics/metrics_web_contents_observer.cc
@@ -667,4 +667,10 @@ void MetricsWebContentsObserver::TestingObserver::OnGoingAway() {
   observer_ = nullptr;
 }
 
+void MetricsWebContentsObserver::BroadcastEventToObservers(
+    const void* const event_key) {
+  if (committed_load_)
+    committed_load_->BroadcastEventToObservers(event_key);
+}
+
 }  // namespace page_load_metrics