1 files changed, 76 insertions, 0 deletions
diff --git a/layout/reftests/transform/partial-prerender-translate-9.html b/layout/reftests/transform/partial-prerender-translate-9.html
new file mode 100644
index 0000000000..2c6af406cb
--- /dev/null
+++ b/layout/reftests/transform/partial-prerender-translate-9.html
@@ -0,0 +1,76 @@
+<!DOCTYPE html>
+<html reftest-async-scroll class="reftest-wait reftest-no-flush">
+<meta name="viewport" content="width=device-width,minimum-scale=1,initial-scale=1">
+<!--
+  A variant test of partial-prerender-translate-5.html but in this test the
+  position:fixed element is inside an iframe.
+  -->
+<style>
+html {
+  overflow: hidden;
+}
+body {
+  margin: 0px;
+  padding: 0px;
+}
+</style>
+<iframe style="width:800px; height:1000px; border: 0"
+        srcdoc="<!DOCTYPE HTML>
+                <html reftest-displayport-x='0' reftest-displayport-y='0'
+                      reftest-displayport-w='800' reftest-displayport-h='2000'
+                      reftest-async-scroll-x='0' reftest-async-scroll-y='1000'>
+                <style>
+                html {
+                  overflow-x: hidden;
+                }
+                html, body {
+                  margin: 0;
+                  padding: 0;
+                }
+                @keyframes anim {
+                  to { transform: translateY(-500px); }
+                }
+                #target {
+                  width: 800px;
+                  height: 1600px;
+                  transform: translateY(-400px);
+                }
+                </style>
+                <div style='width: 800px; height: 2000px'><!-- spacer --></div>
+                <div style='position: fixed; top: 400px'>
+                  <div id='target'>
+                    <!--
+                      Put an SVG element so that the transform display item has
+                      a blob on WebRender which means this test properly fails
+                      without the proper fix.
+                      -->
+                    <svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 800 1600'>
+                      <rect fill='green' y='0'    width='800' height='1000'></rect>
+                      <rect fill='blue'  y='1000' width='800' height='125'></rect>
+                      <rect fill='red'   y='1125' width='800' height='875'></rect>
+                    </svg>
+                  </div>
+                </div>
+                <script>
+                window.addEventListener('message', () => {
+                  if (event.data == 'start') {
+                    target.style.animation = 'anim 100s 1s step-start';
+                    target.addEventListener('animationstart', () => {
+                      parent.postMessage('animationstart', '*');
+                    });
+                  }
+                });
+                </script></html>">
+</iframe>
+<script>
+document.addEventListener("MozReftestInvalidate", () => {
+  document.querySelector("iframe").contentWindow.postMessage("start", "*");
+}, { once: true });
+
+window.addEventListener("message", event => {
+  if (event.data == "animationstart") {
+    document.documentElement.classList.remove('reftest-wait');
+  }
+});
+</script>
+</html>