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diff --git a/layout/base/tests/chrome/test_will_change.html b/layout/base/tests/chrome/test_will_change.html
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+++ b/layout/base/tests/chrome/test_will_change.html
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+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Tests for MozAfterPaint</title>
+  <script type="application/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="chrome://mochikit/content/tests/SimpleTest/paint_listener.js"></script>
+  <style>
+    #checkOpacityRepaint {
+      will-change: opacity;
+    }
+    #checkTransformRepaint {
+      will-change: transform;
+    }
+    div {
+      width: 100px;
+      height: 100px;
+      background: radial-gradient(ellipse at center, #87e0fd 0%,#53cbf1 40%,#05abe0 100%);
+    }
+  </style>
+</head>
+<body>
+  <div id="checkRepaint">
+    Check repaint without will-change
+  </div>
+  <div id="checkOpacityRepaint">
+    Check repaint with will-change
+  </div>
+  <div id="checkTransformRepaint">
+    Check repaint with will-change
+  </div>
+</body>
+<script>
+
+var utils = window.QueryInterface(Components.interfaces.nsIInterfaceRequestor).
+              getInterface(Components.interfaces.nsIDOMWindowUtils);
+
+var initialPaintCount = 0;
+
+function test_checkRepaint(next) {
+  var element = document.getElementById("checkRepaint");
+  waitForAllPaintsFlushed(function () {
+    utils.checkAndClearPaintedState(element);
+    element.style.opacity = "0.5";
+    waitForAllPaintsFlushed(function () {
+      var painted = utils.checkAndClearPaintedState(element);
+      // *** We check that this repaints because the test is relying
+      //     on this property. If this is broken then this test wont
+      //     be reliable check for will-change.
+      is(painted, true, "element should have been painted");
+      next();
+    });
+  });
+}
+
+function test_checkOpacityRepaint(next) {
+  var element = document.getElementById("checkOpacityRepaint");
+  waitForAllPaintsFlushed(function () {
+    utils.checkAndClearPaintedState(element);
+    element.style.opacity = "0.5";
+    waitForAllPaintsFlushed(function () {
+      var painted = utils.checkAndClearPaintedState(element);
+      // BasicLayers' heuristics are so that even with will-change:opacity,
+      // we can still have repaints.
+      if (utils.layerManagerType != "Basic") {
+        is(painted, false, "will-change checkOpacityRepaint element should not have been painted");
+      }
+      next();
+    });
+  });
+}
+
+function test_checkTransformRepaint(next) {
+  var element = document.getElementById("checkTransformRepaint");
+  waitForAllPaintsFlushed(function () {
+    utils.checkAndClearPaintedState(element);
+    element.style.transform = "translateY(-5px)";
+    waitForAllPaintsFlushed(function () {
+      var painted = utils.checkAndClearPaintedState(element);
+      // BasicLayers' heuristics are so that even with will-change:transform,
+      // we can still have repaints.
+      if (utils.layerManagerType != "Basic") {
+        is(painted, false, "will-change checkTransformRepaint element should not have been painted");
+      }
+      next();
+    });
+  });
+}
+
+SimpleTest.waitForExplicitFinish();
+test_checkRepaint(function(){
+  test_checkOpacityRepaint(function(){
+    test_checkTransformRepaint(function(){
+      SimpleTest.finish();
+    });
+  });
+});
+
+</script>
+</html>