The Tor Browser / file revision

 /* Any copyright is dedicated to the Public Domain.

    http://creativecommons.org/publicdomain/zero/1.0/ */

 function test() {

   waitForExplicitFinish();

   let compareCanvasSize = function (prefix, width, height, tabItem) {

     let canvas = tabItem.$canvas[0];

     is(canvas.width, width, prefix + ": canvas widths are equal (" + width + "px)");

     is(canvas.height, height, prefix + ": canvas heights are equal (" + height + "px)");

   };

   newWindowWithTabView(function (win) {

     registerCleanupFunction(function () win.close());

     let cw = win.TabView.getContentWindow();

     let groupItem = cw.GroupItems.groupItems[0];

     let tabItem = groupItem.getChild(0);

     afterAllTabItemsUpdated(function () {

       let {width, height} = tabItem.$canvas[0];

       hideGroupItem(groupItem, function () {

         compareCanvasSize("hidden", width, height, tabItem);

         unhideGroupItem(groupItem, function () {

           compareCanvasSize("unhidden", width, height, tabItem);

           finish();

         });

       });

     }, win);

   });

 }