1 files changed, 48 insertions, 0 deletions
diff --git a/layout/base/tests/test_bug518777.html b/layout/base/tests/test_bug518777.html
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index 000000000..298f18d24
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+++ b/layout/base/tests/test_bug518777.html
@@ -0,0 +1,48 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=518777
+-->
+<head>
+  <title>Test for Bug 518777</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+
+  <script>
+  SimpleTest.waitForExplicitFinish();
+
+  function dotest() {
+    var canvasWidth = 50;
+    var canvasHeight = 50;
+    var source = document.getElementById("source").contentWindow;
+    rect = { left: 25, top: 25,
+             width: canvasWidth, height: canvasHeight };
+    var canvas = SpecialPowers.snapshotRect(source, rect, "transparent");
+    var context = canvas.getContext("2d");
+
+    var data = context.getImageData(0, 0, canvasWidth, canvasHeight).data;
+    var i;
+    for (i = 0; i < data.length; i += 4) {
+      if (data[i] != 0 || data[i + 1] != 0 || data[i + 2] != 255 || data[i + 3] != 255)
+        break;
+    }
+    ok(i >= data.length, "all pixels blue");
+
+    SimpleTest.finish();
+  }
+  </script>
+</head>
+<body>
+<p><a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=518777">Mozilla Bug 518777</a></p>
+
+<!--
+iframe source is
+<html><body onload='window.scrollTo(0,99999999); document.documentElement.offsetWidth; window.parent.dotest();' style='background: rgb(0,0,255); width: 100px; height: 50100px;'></body></html>
+-->
+<iframe id="source" width="50" height="50"
+       src="data:text/html,%3Chtml%3E%3Cbody%20onload%3D%27window.scrollTo%280%2C99999999%29%3B%20document.documentElement.offsetWidth%3B%20window.parent.dotest%28%29%3B%27%20style%3D%27background%3A%20rgb%280%2C0%2C255%29%3B%20width%3A%20100px%3B%20height%3A%2050100px%3B%27%3E%3C%2Fbody%3E%3C%2Fhtml%3E"></iframe>
+
+<pre id="test">
+</pre>
+</body>
+</html>