MD Extensions: Show messages for no extensions, and for no search results

chrome/test/data/webui/extensions/cr_extensions_browsertest.js

Index: chrome/test/data/webui/extensions/cr_extensions_browsertest.js
diff --git a/chrome/test/data/webui/extensions/cr_extensions_browsertest.js b/chrome/test/data/webui/extensions/cr_extensions_browsertest.js
index cfa72f438968b465becb63b8d3a34849828af96e..3a00abd819d6676a790aa364a723a21b1a89759d 100644
--- a/chrome/test/data/webui/extensions/cr_extensions_browsertest.js
+++ b/chrome/test/data/webui/extensions/cr_extensions_browsertest.js
@@ -192,6 +192,12 @@ TEST_F('CrExtensionsBrowserTest', 'ExtensionItemList', function() {
   extension_item_list_tests.registerTests();
   mocha.grep(
       assert(extension_item_list_tests.TestNames.ItemListFiltering)).run();
+  mocha.grep(assert(extension_item_list_tests.TestNames.ItemListNoItemsMsg))
+      .run();
+  mocha
+      .grep(assert(
+          extension_item_list_tests.TestNames.ItemListNoSearchResultsMsg))
+      .run();
 });
 
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