diff --git a/dom/canvas/test/captureStream_common.js b/dom/canvas/test/captureStream_common.js
index 3d0be3602356..778f34d60d05 100644
--- a/dom/canvas/test/captureStream_common.js
+++ b/dom/canvas/test/captureStream_common.js
@@ -42,8 +42,9 @@ CaptureStreamTestHelper.prototype = {
   startDrawing: function (f) {
     var stop = false;
     var draw = () => {
+      if (stop) { return; }
       f();
-      if (!stop) { window.requestAnimationFrame(draw); }
+      window.requestAnimationFrame(draw);
     };
     draw();
     return { stop: () => stop = true };