[Tab Metrics] Measure FP, FCP and FMP for Foreground Tab during Session Restore

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 8aff0dfcde7f78a511d79b206c552bb5e73a3aba..95157e8a8390250d2b09999a53ab3d581b426296 100644
--- a/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
+++ b/chrome/browser/page_load_metrics/page_load_metrics_initialize.cc
@@ -37,6 +37,7 @@
 #include "chrome/browser/page_load_metrics/observers/previews_ukm_observer.h"
 #include "chrome/browser/page_load_metrics/observers/protocol_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/service_worker_page_load_metrics_observer.h"
+#include "chrome/browser/page_load_metrics/observers/session_restore_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/subresource_filter_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/tab_restore_page_load_metrics_observer.h"
 #include "chrome/browser/page_load_metrics/observers/ukm_page_load_metrics_observer.h"
@@ -135,6 +136,11 @@ void PageLoadMetricsEmbedder::RegisterObservers(
                 web_contents_);
     if (loading_predictor_observer)
       tracker->AddObserver(std::move(loading_predictor_observer));
+    std::unique_ptr<page_load_metrics::PageLoadMetricsObserver>
+        session_restore_foreground_tab_observer =
+            SessionRestorePageLoadMetricsObserver::CreateIfNeeded();
+    if (session_restore_foreground_tab_observer)
+      tracker->AddObserver(std::move(session_restore_foreground_tab_observer));
     tracker->AddObserver(
         base::MakeUnique<LocalNetworkRequestsPageLoadMetricsObserver>());
   } else {