Make setZeroTimeout use window.setTimeout

tests/wpt/webgl/tools/set-zero-timeout.patch

@@ -0,0 +1,40 @@
+--- js/webgl-test-utils.js
++++ js/webgl-test-utils.js
+@@ -2876,34 +2876,9 @@ var waitForComposite = function(callback) {
+   countDown();
+ };
+
+-var setZeroTimeout = (function() {
+-  // See https://dbaron.org/log/20100309-faster-timeouts
+-
+-  var timeouts = [];
+-  var messageName = "zero-timeout-message";
+-
+-  // Like setTimeout, but only takes a function argument.  There's
+-  // no time argument (always zero) and no arguments (you have to
+-  // use a closure).
+-  function setZeroTimeout(fn) {
+-      timeouts.push(fn);
+-      window.postMessage(messageName, "*");
+-  }
+-
+-  function handleMessage(event) {
+-      if (event.source == window && event.data == messageName) {
+-          event.stopPropagation();
+-          if (timeouts.length > 0) {
+-              var fn = timeouts.shift();
+-              fn();
+-          }
+-      }
+-  }
+-
+-  window.addEventListener("message", handleMessage, true);
+-
+-  return setZeroTimeout;
+-})();
++var setZeroTimeout = function(handler) {
++  window.setTimeout(handler, 0);
++}
+
+ /**
+  * Runs an array of functions, yielding to the browser between each step.