Bug 1245107 - browser_closeTab.js: wait for the tab to close. r=jaws

The UITour content API call uses sendAsyncMessage so we can't assume a synchronous close.

MozReview-Commit-ID: JXm2ztcLwW5

--HG--
extra : rebase_source : 0a7c3cdcd8e66eb33c56b143fe96b4f5dfd3bfc5

browser/components/uitour/test/browser_closeTab.js

@@ -11,6 +11,8 @@ add_task(setup_UITourTest);
 add_UITour_task(function* test_closeTab() {
   // Setting gTestTab to null indicates that the tab has already been closed,
   // and if this does not happen the test run will fail.
+  let closePromise = BrowserTestUtils.waitForEvent(gBrowser.tabContainer, "TabClose");
   yield gContentAPI.closeTab();
+  yield closePromise;
   gTestTab = null;
 });