layout/style/test/test_flushing_frame.html

   1 <!doctype html>
   2 <meta charset="utf-8">
   3 <title>
   4   Test for bug 1545516: We don't flush layout unnecessarily on the parent
   5   document when the frame is already disconnected.
   6 </title>
   7 <link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
   8 <script src="/tests/SimpleTest/SimpleTest.js"></script>
   9 <div id="content"></div>
  10 <script>
  11   SimpleTest.waitForExplicitFinish();
  12   const iframe = document.createElement("iframe");
  13   const content = document.querySelector("#content");
  14   const parentUtils = SpecialPowers.getDOMWindowUtils(window);
  15   iframe.onload = function() {
  16     const win = iframe.contentWindow;
  17     iframe.offsetTop; // flush layout
  18     content.style.display = "inline"; // Dirty style with something that will reframe.
  19
  20     const previousConstructCount = parentUtils.framesConstructed;
  21     let pagehideRan = false;
  22     win.addEventListener("pagehide", function() {
  23       pagehideRan = true;
  24       win.foo = win.innerWidth;
  25       is(parentUtils.framesConstructed, previousConstructCount, "innerWidth shouldn't have flushed parent document layout")
  26       win.bar = win.document.documentElement.offsetHeight;
  27       is(parentUtils.framesConstructed, previousConstructCount, "offsetHeight shouldn't have flushed parent document layout")
  28       win.baz = win.getComputedStyle(win.document.documentElement).color;
  29       is(parentUtils.framesConstructed, previousConstructCount, "getComputedStyle shouldn't have flushed parent document layout")
  30     });
  31
  32     iframe.remove(); // Remove the iframe
  33     is(pagehideRan, true, "pagehide handler should've ran");
  34     is(parentUtils.framesConstructed, previousConstructCount, "Nothing should've flushed the parent document layout yet");
  35     content.offsetTop;
  36     isnot(parentUtils.framesConstructed, previousConstructCount, "We should've flushed layout now");
  37     SimpleTest.finish();
  38   };
  39   document.body.appendChild(iframe);
  40 </script>