MathML: Wait for Ahem fonts to be ready for displaystyle dynamic tests. (#18614)

Author: fred-wang

mathml/relations/css-styling/displaystyle-013.html

@@ -21,7 +21,10 @@
         document.getElementById("m6").removeAttribute("displaystyle");
         document.documentElement.removeAttribute("class");
       }
-      window.addEventListener("load", doTest);
+      window.addEventListener("load", function() {
+        // Delay the check to workaround WebKit's bug https://webkit.org/b/174030.
+        requestAnimationFrame(() => { document.fonts.ready.then(doTest); });
+      });
     </script>
     <link rel="stylesheet" href="/fonts/ahem.css">
     <style>

mathml/relations/css-styling/displaystyle-014.html

@@ -18,7 +18,10 @@
                  setAttribute('mathbackground', 'red');
         document.documentElement.removeAttribute("class");
       }
-      window.addEventListener("load", doTest);
+      window.addEventListener("load", function() {
+        // Delay the check to workaround WebKit's bug https://webkit.org/b/174030.
+        requestAnimationFrame(() => { document.fonts.ready.then(doTest); });
+      });
     </script>
     <link rel="stylesheet" href="/fonts/ahem.css">
     <style>