From d8bbc7858622b6d9c278469aab701ca0b609cddf Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 15 May 2024 05:35:49 +0200
Subject: Merging upstream version 126.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 .../tests/css/css-viewport/computedStyle-zoom.html | 57 +++++++++++-----------
 .../tests/css/css-viewport/line-height-ref.html    | 23 ---------
 .../tests/css/css-viewport/line-height.html        | 24 ---------
 .../css-viewport/zoom/background-image-ref.html    | 10 ++++
 .../css/css-viewport/zoom/background-image.html    | 13 +++++
 .../tests/css/css-viewport/zoom/basic-ref.html     | 10 ++++
 .../tests/css/css-viewport/zoom/basic.html         | 16 ++++++
 .../tests/css/css-viewport/zoom/font-size-ref.html | 19 ++++++++
 .../tests/css/css-viewport/zoom/font-size.html     | 19 ++++++++
 .../css/css-viewport/zoom/green-square-100px.html  |  3 ++
 .../css-viewport/zoom/image-intrinsic-size.html    | 14 ++++++
 .../css/css-viewport/zoom/inherited-length.html    | 15 ++++++
 .../tests/css/css-viewport/zoom/inherited.html     | 21 ++++++++
 .../css/css-viewport/zoom/line-height-ref.html     | 23 +++++++++
 .../tests/css/css-viewport/zoom/line-height.html   | 24 +++++++++
 .../css-viewport/zoom/parsing/zoom-computed.html   | 23 +++++++++
 .../css/css-viewport/zoom/parsing/zoom-valid.html  | 27 ++++++++++
 .../zoom/relative-units-from-parent-ref.html       |  4 ++
 .../zoom/relative-units-from-parent.html           | 13 +++++
 .../css/css-viewport/zoom/relative-units.html      | 42 ++++++++++++++++
 .../css/css-viewport/zoom/scroll-corner-crash.html |  7 +++
 .../css/css-viewport/zoom/scrollbar-crash.html     |  2 +
 22 files changed, 333 insertions(+), 76 deletions(-)
 delete mode 100644 testing/web-platform/tests/css/css-viewport/line-height-ref.html
 delete mode 100644 testing/web-platform/tests/css/css-viewport/line-height.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/background-image-ref.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/background-image.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/basic-ref.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/basic.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/font-size-ref.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/font-size.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/green-square-100px.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/image-intrinsic-size.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/inherited-length.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/inherited.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/line-height-ref.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/line-height.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-computed.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-valid.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent-ref.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/relative-units.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/scroll-corner-crash.html
 create mode 100644 testing/web-platform/tests/css/css-viewport/zoom/scrollbar-crash.html

(limited to 'testing/web-platform/tests/css/css-viewport')

diff --git a/testing/web-platform/tests/css/css-viewport/computedStyle-zoom.html b/testing/web-platform/tests/css/css-viewport/computedStyle-zoom.html
index 30ed78e30b..82af111bbe 100644
--- a/testing/web-platform/tests/css/css-viewport/computedStyle-zoom.html
+++ b/testing/web-platform/tests/css/css-viewport/computedStyle-zoom.html
@@ -5,23 +5,23 @@
 <link rel="help" href="https://drafts.csswg.org/css-viewport/">
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<head>
-  <style>
-    div {
+<style>
+  div {
     width: 64px;
     height: 64px;
+    line-height: 64px;
+    text-indent: 64px;
     background-color: blue
-    }
-    div.x4_zoom {
+  }
+  div.x4_zoom {
     zoom: 4.0;
     background-color: blueviolet;
-    }
-    div.x2_zoom {
+  }
+  div.x2_zoom {
     background-color: chartreuse;
     zoom: 2.0;
-    }
-
-  </style>
+  }
+</style>
 </head>
 <body>
   <div id="no_zoom"></div>
@@ -29,7 +29,7 @@
   <div class="x2_zoom" id="parent_div">
     <div class="x4_zoom" id="nested_zoom"></div>
   </div>
-  <div class="x2_zoom" id="testing_set_style" style="height: 1px; width: 1px;"></div>
+  <div class="x2_zoom" id="testing_set_style" style="height: 1px; width: 1px; line-height: 1px; text-indent: 1px;"></div>
   <script>
     test(function() {
       assert_true(!!no_zoom, "no zoom target exists");
@@ -37,38 +37,37 @@
       assert_true(!!nested_zoom, "zoom target exists");
       assert_true(!!parent_div, "parent div with zoom exists")
     });
+    function assert_length_props(style, expected) {
+      for (let prop of ["width", "height", "line-height", "text-indent"]) {
+        assert_equals(style.getPropertyValue(prop), expected, prop);
+      }
+    }
     test(function(){
-      noZoomStyle = window.getComputedStyle(no_zoom);
-      assert_equals(noZoomStyle.getPropertyValue("width"), "64px");
-      assert_equals(noZoomStyle.getPropertyValue("height"), "64px");
+      let noZoomStyle = getComputedStyle(no_zoom);
+      assert_length_props(noZoomStyle, "64px");
       assert_equals(noZoomStyle.getPropertyValue("zoom"), "1");
     });
     test(function(){
-      withZoomStyle = window.getComputedStyle(with_zoom);
-      assert_equals(withZoomStyle.getPropertyValue("width"), "64px");
-      assert_equals(withZoomStyle.getPropertyValue("height"), "64px");
+      let withZoomStyle = getComputedStyle(with_zoom);
+      assert_length_props(withZoomStyle, "64px");
       assert_equals(withZoomStyle.getPropertyValue("zoom"), "4");
     });
     test(function(){
-      parentWithZoomStyle = window.getComputedStyle(parent_div);
-      assert_equals(parentWithZoomStyle.getPropertyValue("width"), "64px");
-      assert_equals(parentWithZoomStyle.getPropertyValue("height"), "64px");
+      let parentWithZoomStyle = getComputedStyle(parent_div);
+      assert_length_props(parentWithZoomStyle, "64px");
       assert_equals(parentWithZoomStyle.getPropertyValue("zoom"), "2");
     });
     test(function(){
-      nestedZoomStyle = window.getComputedStyle(nested_zoom);
-      assert_equals(nestedZoomStyle.getPropertyValue("width"), "64px");
-      assert_equals(nestedZoomStyle.getPropertyValue("height"), "64px");
+      nestedZoomStyle = getComputedStyle(nested_zoom);
+      assert_length_props(nestedZoomStyle, "64px");
       assert_equals(nestedZoomStyle.getPropertyValue("zoom"), "4");
     });
     test(function(){
-      testDivStyle = window.getComputedStyle(testing_set_style);
-      assert_equals(testDivStyle.getPropertyValue("width"), "1px");
-      assert_equals(testDivStyle.getPropertyValue("height"), "1px");
+      testDivStyle = getComputedStyle(testing_set_style);
+      assert_length_props(testDivStyle, "1px");
       assert_equals(testDivStyle.getPropertyValue("zoom"), "2");
-      window.testing_set_style.setAttribute("style", "width: 64px; height: 64px;");
-      assert_equals(testDivStyle.getPropertyValue("width"), "64px");
-      assert_equals(testDivStyle.getPropertyValue("height"), "64px");
+      testing_set_style.setAttribute("style", "width: 64px; height: 64px; line-height: 64px; text-indent: 64px;");
+      assert_length_props(testDivStyle, "64px");
       assert_equals(testDivStyle.getPropertyValue("zoom"), "2");
     });
   </script>
diff --git a/testing/web-platform/tests/css/css-viewport/line-height-ref.html b/testing/web-platform/tests/css/css-viewport/line-height-ref.html
deleted file mode 100644
index c75539243c..0000000000
--- a/testing/web-platform/tests/css/css-viewport/line-height-ref.html
+++ /dev/null
@@ -1,23 +0,0 @@
-<!DOCTYPE html>
-<style>CSS zoom applies to line-height when specified and inherited</style>
-<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
-<link rel="help" href="https://drafts.csswg.org/css-viewport/">
-<div style="line-height: 12px; font-size: 12px">
-  Double-spaced<br>12px font text
-</div>
-
-<hr>
-
-<div style="line-height: 24px; font-size: 24px;">
-  Double-spaced<br>12px font zoomed text
-</div>
-
-<hr>
-
-<div style="line-height: 12px; font-size: 12px">
-  <div style="line-height: 24px; font-size: 24px">
-    Double-spaced<br>12px font zoomed inherited text
-  </div>
-</div>
-
-<hr>
diff --git a/testing/web-platform/tests/css/css-viewport/line-height.html b/testing/web-platform/tests/css/css-viewport/line-height.html
deleted file mode 100644
index fa333be32f..0000000000
--- a/testing/web-platform/tests/css/css-viewport/line-height.html
+++ /dev/null
@@ -1,24 +0,0 @@
-<!DOCTYPE html>
-<style>CSS zoom applies to line-height when specified and inherited</style>
-<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
-<link rel="help" href="https://drafts.csswg.org/css-viewport/">
-<link rel="match" href="line-height-ref.html">
-<div style="line-height: 12px; font-size: 12px">
-  Double-spaced<br>12px font text
-</div>
-
-<hr>
-
-<div style="line-height: 12px; font-size: 12px; zoom: 2">
-  Double-spaced<br>12px font zoomed text
-</div>
-
-<hr>
-
-<div style="line-height: 12px; font-size: 12px">
-  <div style="zoom:2">
-    Double-spaced<br>12px font zoomed inherited text
-  </div>
-</div>
-
-<hr>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/background-image-ref.html b/testing/web-platform/tests/css/css-viewport/zoom/background-image-ref.html
new file mode 100644
index 0000000000..6fe548f343
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/background-image-ref.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<title>CSS Test Reference</title>
+<style>
+div {
+  width: 10px;
+  height: 10px;
+  background-image: image-set(url("/images/pattern.png") 2x);
+}
+</style>
+<div></div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/background-image.html b/testing/web-platform/tests/css/css-viewport/zoom/background-image.html
new file mode 100644
index 0000000000..805dad187d
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/background-image.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<title>Zoom affects background-image intrinsic sizes</title>
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<link rel="match" href="background-image-ref.html">
+<style>
+div {
+  width: 20px;
+  height: 20px;
+  zoom: 0.5;
+  background-image: url("/images/pattern.png"); /* 20x20 */
+}
+</style>
+<div></div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/basic-ref.html b/testing/web-platform/tests/css/css-viewport/zoom/basic-ref.html
new file mode 100644
index 0000000000..5de90caf7f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/basic-ref.html
@@ -0,0 +1,10 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>CSS test reference</title>
+<style>
+div {
+  background-color: green;
+}
+</style>
+<div style="width: 100px; height: 100px"></div>
+<div style="width: 200px; height: 200px;"></div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/basic.html b/testing/web-platform/tests/css/css-viewport/zoom/basic.html
new file mode 100644
index 0000000000..580d3c83cd
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/basic.html
@@ -0,0 +1,16 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>zoom property: basic test</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="author" href="https://mozilla.com" title="Mozilla">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<link rel="match" href="basic-ref.html">
+<style>
+div {
+  width: 100px;
+  height: 100px;
+  background-color: green;
+}
+</style>
+<div></div>
+<div style="zoom: 2"></div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/font-size-ref.html b/testing/web-platform/tests/css/css-viewport/zoom/font-size-ref.html
new file mode 100644
index 0000000000..5714a878b3
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/font-size-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<style>CSS Test reference</style>
+<div style="font-size: 12px">
+  12px text
+</div>
+
+<hr>
+
+<div style="font-size: 24px;">
+  12px zoomed text
+</div>
+
+<hr>
+
+<div style="font-size: 12px">
+  <div style="font-size: 24px">
+    12px zoomed inherited text
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/font-size.html b/testing/web-platform/tests/css/css-viewport/zoom/font-size.html
new file mode 100644
index 0000000000..e4b20c3c93
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/font-size.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<style>CSS zoom applies to font-size when specified and inherited</style>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/">
+<link rel="match" href="font-size-ref.html">
+<div style="font-size: 12px">
+  12px text
+</div>
+<hr>
+<div style="font-size: 12px; zoom: 2">
+  12px zoomed text
+</div>
+<hr>
+<div style="font-size: 12px">
+  <div style="zoom:2">
+    12px zoomed inherited text
+  </div>
+</div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/green-square-100px.html b/testing/web-platform/tests/css/css-viewport/zoom/green-square-100px.html
new file mode 100644
index 0000000000..6677176230
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/green-square-100px.html
@@ -0,0 +1,3 @@
+<!doctype html>
+<meta charset="utf-8">
+<div style="width: 100px; height: 100px; background-color: green"></div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/image-intrinsic-size.html b/testing/web-platform/tests/css/css-viewport/zoom/image-intrinsic-size.html
new file mode 100644
index 0000000000..d152bb24ee
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/image-intrinsic-size.html
@@ -0,0 +1,14 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>Zoom affects image intrinsic sizes</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<link rel="match" href="background-image-ref.html">
+<style>
+img {
+  vertical-align: top;
+  zoom: .5;
+}
+</style>
+<img src="/images/pattern.png">
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/inherited-length.html b/testing/web-platform/tests/css/css-viewport/zoom/inherited-length.html
new file mode 100644
index 0000000000..d83111a435
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/inherited-length.html
@@ -0,0 +1,15 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>zoom property: inherited length into zoom</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="author" href="https://mozilla.com" title="Mozilla">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<link rel="match" href="green-square-100px.html">
+<style>
+div {
+  background-color: green;
+}
+</style>
+<div style="width: 100px; height: 100px;">
+  <div style="zoom: 2; width: inherit;"></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/inherited.html b/testing/web-platform/tests/css/css-viewport/zoom/inherited.html
new file mode 100644
index 0000000000..2c8ad1694a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/inherited.html
@@ -0,0 +1,21 @@
+<!doctype html>
+<meta charset="utf-8">
+<title>Effective zoom value is inherited</title>
+<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
+<link rel="author" href="https://mozilla.com" title="Mozilla">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<link rel="match" href="basic-ref.html">
+<style>
+.container {
+  zoom: 2;
+}
+.child {
+  width: 100px;
+  height: 100px;
+  background-color: green;
+}
+</style>
+<div class="child"></div>
+<div class="container">
+  <div class="child"></div>
+</div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/line-height-ref.html b/testing/web-platform/tests/css/css-viewport/zoom/line-height-ref.html
new file mode 100644
index 0000000000..c75539243c
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/line-height-ref.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<style>CSS zoom applies to line-height when specified and inherited</style>
+<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/">
+<div style="line-height: 12px; font-size: 12px">
+  Double-spaced<br>12px font text
+</div>
+
+<hr>
+
+<div style="line-height: 24px; font-size: 24px;">
+  Double-spaced<br>12px font zoomed text
+</div>
+
+<hr>
+
+<div style="line-height: 12px; font-size: 12px">
+  <div style="line-height: 24px; font-size: 24px">
+    Double-spaced<br>12px font zoomed inherited text
+  </div>
+</div>
+
+<hr>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/line-height.html b/testing/web-platform/tests/css/css-viewport/zoom/line-height.html
new file mode 100644
index 0000000000..fa333be32f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/line-height.html
@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<style>CSS zoom applies to line-height when specified and inherited</style>
+<link rel="author" title="Chris Harrelson" href="mailto:chrishtr@chromium.org">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/">
+<link rel="match" href="line-height-ref.html">
+<div style="line-height: 12px; font-size: 12px">
+  Double-spaced<br>12px font text
+</div>
+
+<hr>
+
+<div style="line-height: 12px; font-size: 12px; zoom: 2">
+  Double-spaced<br>12px font zoomed text
+</div>
+
+<hr>
+
+<div style="line-height: 12px; font-size: 12px">
+  <div style="zoom:2">
+    Double-spaced<br>12px font zoomed inherited text
+  </div>
+</div>
+
+<hr>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-computed.html b/testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-computed.html
new file mode 100644
index 0000000000..41fb1b24ae
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-computed.html
@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: getComputedStyle().zoom</title>
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/computed-testcommon.js"></script>
+<div id="target"></div>
+<script>
+test_computed_value("zoom", "normal", "1");
+
+test_computed_value("zoom", "1", "1");
+test_computed_value("zoom", "1.5", "1.5");
+test_computed_value("zoom", "0.75", "0.75");
+
+test_computed_value("zoom", "100%", "1");
+test_computed_value("zoom", "150%", "1.5");
+test_computed_value("zoom", "75%", "0.75");
+
+// Legacy crap, wat
+test_computed_value("zoom", "0", "1");
+test_computed_value("zoom", "0%", "1");
+</script>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-valid.html b/testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-valid.html
new file mode 100644
index 0000000000..3f36508b8b
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/parsing/zoom-valid.html
@@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>CSS Test: parsing zoom with valid and invalid values</title>
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.com">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="/css/support/parsing-testcommon.js"></script>
+<body>
+<script>
+test_valid_value("zoom", "normal");
+test_valid_value("zoom", "1");
+test_valid_value("zoom", "100%");
+test_valid_value("zoom", "0");
+test_valid_value("zoom", "0%");
+test_valid_value("zoom", "1.5");
+test_valid_value("zoom", "150%")
+test_valid_value("zoom", "75%");
+test_valid_value("zoom", "0.5");
+
+test_invalid_value("zoom", "auto");
+test_invalid_value("zoom", "-100%");
+test_invalid_value("zoom", "-200%");
+test_invalid_value("zoom", "-1");
+test_invalid_value("zoom", "-2");
+</script>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent-ref.html b/testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent-ref.html
new file mode 100644
index 0000000000..4e7456ce71
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent-ref.html
@@ -0,0 +1,4 @@
+<!doctype html>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width">
+<div style="font-size: 4em; line-height: 4lh">ABC</div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent.html b/testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent.html
new file mode 100644
index 0000000000..57df82b6f1
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/relative-units-from-parent.html
@@ -0,0 +1,13 @@
+<!doctype html>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1892676">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<link rel="match" href="relative-units-from-parent-ref.html">
+<!--
+  The font-size and line-height use the parent sizes, but should still
+  multiply by our own zoom.
+-->
+<div style="zoom: 2; font-size: 2em; line-height: 2lh">ABC</div>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/relative-units.html b/testing/web-platform/tests/css/css-viewport/zoom/relative-units.html
new file mode 100644
index 0000000000..8cfa27c93a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/relative-units.html
@@ -0,0 +1,42 @@
+<!doctype html>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width">
+<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
+<link rel="author" title="Mozilla" href="https://mozilla.org">
+<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1892676">
+<link rel="help" href="https://drafts.csswg.org/css-viewport/#zoom-property">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<style>
+  :root,
+  #zoomed {
+    font-size: 10px;
+    line-height: 10px;
+    zoom: 2;
+  }
+</style>
+<div id="outside"></div>
+<div id="zoomed">
+  <div id="inside"></div>
+</div>
+<script>
+  function test_unit(unit, outside, zoomed, inside = zoomed) {
+    test(function() {
+      let values = { outside, zoomed, inside };
+      for (let id of ["outside", "zoomed", "inside"]) {
+        let el = document.getElementById(id);
+        el.style.height = "1" + unit;
+        // approx_equals is needed because innerHeight / innerWidth round.
+        assert_approx_equals(el.getBoundingClientRect().height, values[id], 1, `${unit} in ${id}`);
+        el.style.height = "";
+      }
+    });
+  }
+
+  test_unit("em", 20, 40);
+  test_unit("rem", 20, 40);
+  test_unit("lh", 20, 40);
+  test_unit("rlh", 20, 40);
+  test_unit("vh", 2 * innerHeight / 100, 4 * innerHeight / 100);
+  test_unit("vw", 2 * innerWidth / 100, 4 * innerWidth / 100);
+</script>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/scroll-corner-crash.html b/testing/web-platform/tests/css/css-viewport/zoom/scroll-corner-crash.html
new file mode 100644
index 0000000000..0ec88deb74
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/scroll-corner-crash.html
@@ -0,0 +1,7 @@
+<style>
+* {
+  overflow: scroll scroll;
+}
+</style>
+<h4 style="zoom: 3">
+<figure>
diff --git a/testing/web-platform/tests/css/css-viewport/zoom/scrollbar-crash.html b/testing/web-platform/tests/css/css-viewport/zoom/scrollbar-crash.html
new file mode 100644
index 0000000000..791022407f
--- /dev/null
+++ b/testing/web-platform/tests/css/css-viewport/zoom/scrollbar-crash.html
@@ -0,0 +1,2 @@
+<textarea style="zoom: 0.20">
+
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