MD History: Delete button in the toolbar allows deletion of multiple history-items.

chrome/test/data/webui/md_history/history_card_test.js

Index: chrome/test/data/webui/md_history/history_card_test.js
diff --git a/chrome/test/data/webui/md_history/history_card_test.js b/chrome/test/data/webui/md_history/history_card_test.js
index 25c5fa4a01159fcd97058215f08e070f88882d82..af661a256bd892e47f5a605f7b1556f6f939eb77 100644
--- a/chrome/test/data/webui/md_history/history_card_test.js
+++ b/chrome/test/data/webui/md_history/history_card_test.js
@@ -5,13 +5,18 @@
 cr.define('md_history.history_card_test', function() {
   function registerTests() {
     suite('history-card', function() {
-      test('basic separator insertion', function(done) {
-        var element = document.createElement('history-card');
+      var element;
+
+      suiteSetup(function() {
+        element = document.createElement('history-card');
         element.historyItems = [
           {"time": "1000000000"},
           {"time": "10000000"},
           {"time": "900000"}
         ];
+      })
+
+      test('basic separator insertion', function(done) {
         flush(function() {
           // Check that the correct number of time gaps are inserted.
           var spacers =
@@ -20,6 +25,31 @@ cr.define('md_history.history_card_test', function() {
           done();
         });
       });
+
+      test('separator insertion when items change but item list length stays ' +
+          'the same', function(done) {
+        element.set('historyItems', [{"time": "900000"},
+                                     {"time": "900000"},
+                                     {"time": "900000"}]);
+
+        flush(function() {
+          var items =
+            Polymer.dom(element.root).querySelectorAll('history-item');
+          var spacers =
+            Polymer.dom(element.root).querySelectorAll('#time-gap-separator');
+
+          assertEquals('900000', items[0].timestamp_);
+          assertEquals('900000', items[1].timestamp_);
+          assertEquals('900000', items[2].timestamp_);
+
+          // Note that the spacers aren't actually removed, are just set to:
+          // display: none;
+          for (var i = 0; i < spacers.length; i++) {
+            assertEquals(spacers[i].style.display, 'none');
+          }
+          done();
+        });
+      });
     });
   }
   return {