Throttle rendering pipeline for invisible iframes

LayoutTests/fast/repaint/resources/ensure-no-repaints.js

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+window.testIsAsync = true;
+
+// Spin for a few frames looking for repaints. We shouldn't see any.
+var frameCount = 10;

[esprehn, 2015/09/21 21:27:20]

This is racy, we don't want to do this. Can you write a Sim* test instead? See
DocumentLoadingRenderingTest. You want to add real ASSERTs at the repaint/paint
level.

[Sami, 2015/09/23 18:31:06]

Neat, I did't know those were a thing. Done.

+function repaintTest()
+{
+    if (--frameCount)
+        window.requestAnimationFrame(repaintTest);
+    else
+        finishRepaintTest();
+}
+
+window.addEventListener('load', runRepaintTest);