[Page Load Metrics] Add page load metrics for omnibox.

chrome/browser/page_load_metrics/page_load_metrics_initialize.cc

Index: chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
diff --git a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
index ffca7008daa12fb5af7de0a9b2cb6b609782d498..126874390fb1a11920db86d09e3ae2091e252371 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
@@ -20,6 +20,7 @@
 #include "chrome/browser/page_load_metrics/observers/google_captcha_observer.h"
 #include "chrome/browser/page_load_metrics/observers/https_engagement_metrics/https_engagement_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/no_state_prefetch_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/observers/omnibox_suggestion_used_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/prerender_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/previews_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/protocol_page_load_metrics_observer.h"
@@ -119,6 +120,8 @@ void PageLoadMetricsEmbedder::RegisterObservers(
     if (prerender_observer)
       tracker->AddObserver(std::move(prerender_observer));
   }
+  tracker->AddObserver(
+      base::MakeUnique<OmniboxSuggestionUsedMetricsObserver>(IsPrerendering()));
 }
 
 bool PageLoadMetricsEmbedder::IsPrerendering() const {