Bug 1415793 - Check the removal of a tab until next tick. r=rpl

--HG--
extra : rebase_source : 2a4937ec1816cdd943c6d15de2b34a73e8890693

mobile/android/components/extensions/test/mochitest/test_ext_activeTab_permission.html

@@ -315,7 +315,7 @@ add_task(async function test_activeTab_pageAction_popup() {
   const popupTabId = popupTab.id;
 
   let onceTabClosed = new Promise(resolve => {
-    BrowserApp.deck.addEventListener("TabClose", resolve, {once: true});
+    BrowserApp.deck.addEventListener("TabClose", () => setTimeout(resolve, 0), {once: true});
   });
 
   // Switch to the parent tab of the popup tab.
@@ -444,7 +444,7 @@ add_task(async function test_activeTab_browserAction_popup() {
   const popupTabId = popupTab.id;
 
   let onceTabClosed = new Promise(resolve => {
-    BrowserApp.deck.addEventListener("TabClose", resolve, {once: true});
+    BrowserApp.deck.addEventListener("TabClose", () => setTimeout(resolve, 0), {once: true});
   });
 
   // Switch to the parent tab of the popup tab.