Add enable-service-worker-navigation-preload flag in chrome://flags

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index c1c8b66fe0d230601fecf34a777971ca8b991a2e..e4493aec087ec3f687ff7f99daed5fa02a0d7a73 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -96100,6 +96100,7 @@ value.
   <int value="1209221384" label="enable-experimental-accessibility-features"/>
   <int value="1210343926" label="enable-drop-sync-credential"/>
   <int value="1219628795" label="PrintScaling:disabled"/>
+  <int value="1219826373" label="ServiceWorkerNavigationPreload:enabled"/>
   <int value="1220171692" label="SpeculativeLaunchServiceWorker:enabled"/>
   <int value="1220464509" label="enable-first-run-ui-transitions"/>
   <int value="1221559505" label="enable-spelling-feedback-field-trial"/>
@@ -96183,6 +96184,7 @@ value.
   <int value="1511161758" label="BackgroundLoader:enabled"/>
   <int value="1515196403" label="fast-user-switching"/>
   <int value="1517863401" label="history-entry-requires-user-gesture"/>
+  <int value="1541723759" label="ServiceWorkerNavigationPreload:disabled"/>
   <int value="1548776701" label="AllBookmarks:disabled"/>
   <int value="1548942246" label="PassiveDocumentEventListeners:disabled"/>
   <int value="1560188739" label="reader-mode-heuristics"/>