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diff --git a/layout/base/tests/test_flush_on_paint.html b/layout/base/tests/test_flush_on_paint.html
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+++ b/layout/base/tests/test_flush_on_paint.html
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+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test that we flush before painting</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body onload="doIteration()">
+<p id="display"></p>
+<div id="content" style="display: none">
+</div>
+<embed type="application/x-test" id="plugin" drawmode="solid" style="width:200px; height:200px;"></embed>
+<pre id="test">
+<script type="application/javascript">
+SimpleTest.waitForExplicitFinish();
+SimpleTest.requestFlakyTimeout("This test deals with painting and invalidation. " +
+                               "Those are tricky to detect, so we have to poll here, which means that we have to rely on flaky timeouts. " +
+                               "This special case is safe because we're only polling for events.");
+
+var iterations = 0;
+var plugin = document.getElementById("plugin");
+var lastPaintCount;
+var expectedWidth;
+
+var toggle = true;
+function invalidationLoop() {
+  toggle = !toggle;
+  var color = toggle ? "8F" : "00";
+  plugin.setColor("FFFFFF" + color);
+  setTimeout(invalidationLoop, 20);
+}
+invalidationLoop();
+
+function doIteration() {
+  lastPaintCount = window.mozPaintCount;
+  ok(true, "Beginning iteration " + iterations + ", last paint count: " + lastPaintCount);
+
+  expectedWidth = 201 + iterations;
+  plugin.style.width = expectedWidth + "px";
+  checkDone();
+}
+
+function checkDone() {
+  ok(true, "Check to see if we're done: " + window.mozPaintCount);
+  if (window.mozPaintCount == lastPaintCount) {
+    setTimeout(checkDone, 30);
+    return;
+  }
+
+  var utils = SpecialPowers.getDOMWindowUtils(window);
+  is(plugin.getWidthAtLastPaint(), utils.screenPixelsPerCSSPixel*expectedWidth,
+     "Check that we set width before painting");
+
+  ++iterations;
+  if (iterations < 100) {
+    doIteration();
+  } else {
+    SimpleTest.finish();
+  }
+}
+</script>
+</pre>
+</body>
+</html>