import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

layout/style/test/test_contain_formatting_context.html

@@ -0,0 +1,40 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1170781
+-->
+<head>
+  <meta charset="utf-8">
+  <title>Test that 'contain: paint' updates 'display' correctly</title>
+  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="property_database.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+</head>
+<body>
+  <div id="test" style="contain: paint"></div>
+  <script>
+  // This mapping is currently mostly based off of a bugzilla comment by Tab
+  // Atkins Jr. in bug 1179349. Ultimately, it should be based on a
+  // specification.
+
+  // XXX 'ruby[-*]' and 'run-in' might need to be added here.
+  var expectedChanges = {
+    'inline'              : 'inline-block',
+  };
+  var displayInfo = gCSSProperties["display"];
+  var test = document.getElementById('test');
+  var displayVals = displayInfo.initial_values.concat(displayInfo.other_values);
+  for (dispVal of displayVals) {
+    test.style.display = dispVal;
+    if (expectedChanges.hasOwnProperty(dispVal)) {
+      is(getComputedStyle(test).display, expectedChanges[dispVal],
+          `'contain: paint' should change 'display: ${dispVal}' to ` +
+          `'display: ${expectedChanges[dispVal]}'`);
+    } else {
+      is(getComputedStyle(test).display, dispVal,
+          `'contain: paint' should not change 'display: ${dispVal}'`);
+    }
+  }
+  </script>
+</body>
+</html>