diff -r 000000000000 -r 6474c204b198 toolkit/components/places/tests/unit/test_PlacesUtils_lazyobservers.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toolkit/components/places/tests/unit/test_PlacesUtils_lazyobservers.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,47 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+function run_test() {
+  do_test_pending();
+  
+  const TEST_URI = NetUtil.newURI("http://moz.org/")
+  let observer = {
+    QueryInterface: XPCOMUtils.generateQI([
+      Ci.nsINavBookmarkObserver,
+    ]),
+
+    onBeginUpdateBatch: function () {},
+    onEndUpdateBatch: function () {},
+    onItemAdded: function (aItemId, aParentId, aIndex, aItemType, aURI) {
+      do_check_true(aURI.equals(TEST_URI));
+      PlacesUtils.removeLazyBookmarkObserver(this);
+      do_test_finished();
+    },
+    onItemRemoved: function () {},
+    onItemChanged: function () {},
+    onItemVisited: function () {},
+    onItemMoved: function () {},
+  };
+
+  // Check registration and removal with uninitialized bookmarks service.
+  PlacesUtils.addLazyBookmarkObserver(observer);
+  PlacesUtils.removeLazyBookmarkObserver(observer);
+
+  // Add a proper lazy observer we will test.
+  PlacesUtils.addLazyBookmarkObserver(observer);
+
+  // Check that we don't leak when adding and removing an observer while the
+  // bookmarks service is instantiated but no change happened (bug 721319).
+  PlacesUtils.bookmarks;
+  PlacesUtils.addLazyBookmarkObserver(observer);
+  PlacesUtils.removeLazyBookmarkObserver(observer);
+  try {
+    PlacesUtils.bookmarks.removeObserver(observer);
+    do_throw("Trying to remove a nonexisting observer should throw!");
+  } catch (ex) {}
+
+  PlacesUtils.bookmarks.insertBookmark(PlacesUtils.unfiledBookmarksFolderId,
+                                       TEST_URI,
+                                       PlacesUtils.bookmarks.DEFAULT_INDEX,
+                                       "Bookmark title");
+}