file_synthmousemove_after_navigation.html

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<!doctype html>

<style>

  html, body { margin: 0; padding: 0; height: 100%; }

  body { background: white; }

  body:hover { background: red; }

</style>

<script src="/tests/SimpleTest/SimpleTest.js"></script>

<script src="/tests/SimpleTest/EventUtils.js"></script>

<script>

async function runTest() {

  const isReloaded = sessionStorage.getItem("bug2038491_reloaded") === "true";

  if (!isReloaded) {

    // First load: synthesize a real mouse move at a known position so the

    // root PresShell records the mouse state, then reload to drop that

    // PresShell.

    synthesizeMouse(document.body, 100, 100, { type: "mousemove" });

    // Wait one paint tick so the synth move propagates and :hover is applied.

    await new Promise(r => requestAnimationFrame(r));

    await new Promise(r => requestAnimationFrame(r));

    const bg = getComputedStyle(document.body).backgroundColor;

    if (bg !== "rgb(255, 0, 0)") {

      opener.reportResult(

        false,

        `Setup: body should be red (hovered) after initial mouse move, got ${bg}`

);

      window.close();

      return;

    sessionStorage.setItem("bug2038491_reloaded", "true");

    location.reload();

    return;

  // Second load: the new root PresShell has no per-PresShell mouse state.

  // PointerEventHandler::sLastMouseInfo still holds the cached position from

  // before the reload, with a dead weak ref to the old PresShell. The fix

  // for bug 2038491 lets PresShell::SynthesizeMouseMove claim that orphaned

  // state. PresShell::UnsuppressAndInvalidate calls SynthesizeMouseMove

  // when painting unsuppresses; with the fix in place a synthetic eMouseMove

  // dispatches and re-evaluates :hover on the new document.

  // Give the refresh driver several ticks to dispatch the synthetic mouse

  // move.

  for (let i = 0; i < 10; i++) {

    await new Promise(r => requestAnimationFrame(r));

  const bg = getComputedStyle(document.body).backgroundColor;

  const passed = bg === "rgb(255, 0, 0)";

  sessionStorage.removeItem("bug2038491_reloaded");

  opener.reportResult(

    passed,

    passed

      ? "body is red (hovered) after navigation without a fresh mouse move"

      : `body should be red (hovered) after navigation, got ${bg}`

);

  window.close();

SimpleTest.waitForFocus(runTest);

</script>

<body></body>