Bug 1395281 - Fix perma-red in browser_aboutHome_wrapsCorrectly.js when Activity Stream is enabled for about:home r=Mardak

MozReview-Commit-ID: D85bXwro80e

--HG--
extra : rebase_source : 5e497a20fd6e2360f1bcb30c10bcb839097eb322

browser/base/content/test/about/browser_aboutHome_wrapsCorrectly.js

@@ -1,4 +1,9 @@
 add_task(async function() {
+  // When about:home is set to Activity Stream, there are no 'narrow' attributes
+  // therefore for this test, we want to ensure we're using the original about:home
+  await SpecialPowers.pushPrefEnv({set: [
+    ["browser.newtabpage.activity-stream.aboutHome.enabled", false]
+  ]});
   let newWindow = await BrowserTestUtils.openNewBrowserWindow();
 
   let resizedPromise = BrowserTestUtils.waitForEvent(newWindow, "resize");