MD Settings: Restore message shown when no "zoom" exceptions exist.

chrome/test/data/webui/settings/zoom_levels_tests.js

Index: chrome/test/data/webui/settings/zoom_levels_tests.js
diff --git a/chrome/test/data/webui/settings/zoom_levels_tests.js b/chrome/test/data/webui/settings/zoom_levels_tests.js
index 82d79ff13f257abfcc75ce6f5b1de172e99e4c23..3ac5a41726cdc16f47c16eaf093a85615ccb3f3d 100644
--- a/chrome/test/data/webui/settings/zoom_levels_tests.js
+++ b/chrome/test/data/webui/settings/zoom_levels_tests.js
@@ -75,6 +75,9 @@ cr.define('zoom_levels', function() {
         var list = testElement.$.list;
         assertTrue(!!list);
         assertEquals(0, list.items.length);
+        assertEquals(
+            0, testElement.shadowRoot.querySelectorAll('.list-item').length);
+        assertTrue(!!testElement.$$('#empty'));
       });
 
       test('non-empty zoom state', function() {
@@ -84,6 +87,9 @@ cr.define('zoom_levels', function() {
           var list = testElement.$.list;
           assertTrue(!!list);
           assertEquals(2, list.items.length);
+          assertFalse(!!testElement.$$('#empty'));
+          assertEquals(
+              2, testElement.shadowRoot.querySelectorAll('.list-item').length);
 
           var removeButton =
               getRemoveButton(testElement.$.listContainer, 0);