<!doctype HTML>
<html>
<meta charset="utf8">
<title>Display Locking: style on hidden element & child</title>
<link rel="author" title="Rakina Zata Amni" href="mailto:rakina@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
<meta name="assert" content="style is available for content-visibility hidden elements">

<style>
.hidden {
  content-visibility: hidden;
}
</style>
<div id="container" class=hidden>
  <div id="child">
    <div id="grandchild"></div>
  </div>
</div>

<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<script>
async_test((t) => {
  async function runTest() {
    let container = document.getElementById("container");
    container.style = "color: blue;";
    t.step(() => assert_equals(getComputedStyle(container).color, "rgb(0, 0, 255)", "container color changed to blue"));
    t.step(() => assert_equals(getComputedStyle(child).color, "rgb(0, 0, 255)", "child inherits blue color"));
    t.step(() => assert_equals(getComputedStyle(grandchild).color, "rgb(0, 0, 255)", "grandchild inherits blue color"));

    child.style = "color: green;";
    t.step(() => assert_equals(getComputedStyle(container).color, "rgb(0, 0, 255)", "container color is still blue"));
    t.step(() => assert_equals(getComputedStyle(child).color, "rgb(0, 128, 0)", "child color changed to green"));
    t.step(() => assert_equals(getComputedStyle(grandchild).color, "rgb(0, 128, 0)", "grandchild inherits green color"));

    child.style = "";

    // Commit container, lock child.
    container.classList.remove("hidden");
    child.classList.add("hidden");
    requestAnimationFrame(() => {
      // Update style outside of the hidden subtree.
      container.style = "color: red;";
      container.offsetTop;

      // Inheritance works as usual through hidden boundaries.
      t.step(() => assert_equals(getComputedStyle(grandchild).color, "rgb(255, 0, 0)", "grandchild inherits red color"));
      t.step(() => assert_equals(getComputedStyle(child).color, "rgb(255, 0, 0)", "child inherits red color"));
      t.step(() => assert_equals(getComputedStyle(container).color, "rgb(255, 0, 0)", "container color changed to red"));

      t.done();
    });
  }

  window.onload = function() {
    requestAnimationFrame(() => requestAnimationFrame(runTest));
  };
}, "getComputedStyle gets up-to-date style");
</script>

