Add empty list indicator for Physical Web WebUI

components/physical_web/webui/resources/physical_web.js

Index: components/physical_web/webui/resources/physical_web.js
diff --git a/components/physical_web/webui/resources/physical_web.js b/components/physical_web/webui/resources/physical_web.js
index 418dc1d6e90c1b5e8daffb35b8fbd841900eae08..2029936b8da52f242319ca3cf7dad37d11587a38 100644
--- a/components/physical_web/webui/resources/physical_web.js
+++ b/components/physical_web/webui/resources/physical_web.js
@@ -24,8 +24,12 @@ function physicalWebItemClicked(index) {
 function returnNearbyURLs(nearbyUrlsData) {
   var bodyContainer = $('body-container');
   renderTemplate(nearbyUrlsData);
+  bodyContainer.style.display = 'block';
 
-  bodyContainer.style.visibility = 'visible';
+  if (nearbyUrlsData['metadata'].length == 0) {
+    var emptyMessage = $('empty-list-container');
+    emptyMessage.style.display = 'block';
+  }
 }
 
 document.addEventListener('DOMContentLoaded', requestNearbyURLs);