Merge pull request #155 from bakulf/delete

Comment applied - issue #151

index.js

@@ -236,13 +236,7 @@ const ContainerService = {
       return Promise.resolve(null);
     }
 
-    const browserWin = windowUtils.getMostRecentBrowserWindow();
+    return this._recentBrowserWindow().then(browserWin => {
-
-    // This should not really happen.
-    if (!browserWin || !browserWin.gBrowser) {
-      return Promise.resolve(null);
-    }
-
       browserWin.gBrowser.addTab();
 
       for (let tab of tabsToClose) { // eslint-disable-line prefer-const
@@ -250,6 +244,18 @@ const ContainerService = {
       }
 
       return Promise.resolve(null);
+    }).catch(() => null);
+  },
+
+  _recentBrowserWindow() {
+    const browserWin = windowUtils.getMostRecentBrowserWindow();
+
+    // This should not really happen.
+    if (!browserWin || !browserWin.gBrowser) {
+      return Promise.resolve(null);
+    }
+
+    return Promise.resolve(browserWin);
   },
 
   // Tabs management
@@ -456,14 +462,7 @@ const ContainerService = {
   },
 
   openTab(args) {
-    return new Promise(resolve => {
+    return this._recentBrowserWindow().then(browserWin => {
-      const browserWin = windowUtils.getMostRecentBrowserWindow();
-
-      // This should not really happen.
-      if (!browserWin || !browserWin.gBrowser) {
-        return Promise.resolve(false);
-      }
-
       let userContextId = 0;
       if ("userContextId" in args) {
         userContextId = args.userContextId;
@@ -471,8 +470,8 @@ const ContainerService = {
 
       const tab = browserWin.gBrowser.addTab(args.url || null, { userContextId });
       browserWin.gBrowser.selectedTab = tab;
-      resolve(true);
+      return true;
-    });
+    }).catch(() => false);
   },
 
   // Identities management