HTML: BarProp objects

For whatwg/html#2579.

html/browsers/the-window-object/BarProp.window.js

@@ -0,0 +1,59 @@
+function assert_barProps(barPropObjects, visible) {
+  let lastBarProp = undefined;
+  for (const currentBarProp of barPropObjects) {
+    assert_not_equals(currentBarProp, lastBarProp, "BarBrop objects of different properties are identical");
+    assert_equals(currentBarProp.visible, visible, "a BarProp's visible is wrong");
+    lastBarProp = currentBarProp;
+  }
+}
+
+function assert_identical_barProps(barProps, w, oldBarPropObjects, visible) {
+  barProps.map(val => w[val]).map((val, index) => {
+    assert_equals(val, oldBarPropObjects[index], "BarProp identity not preserved");
+  });
+  assert_barProps(oldBarPropObjects, visible);
+}
+
+async_test(t => {
+  const frame = document.body.appendChild(document.createElement("iframe")),
+        frameW = frame.contentWindow,
+        barProps = ["locationbar", "menubar", "personalbar", "scrollbars", "statusbar", "toolbar"],
+        barPropObjects = barProps.map(val => frameW[val]);
+
+  assert_barProps(barPropObjects, true);
+  frame.remove();
+  assert_identical_barProps(barProps, frameW, barPropObjects, false);
+  t.step_timeout(() => {
+    assert_identical_barProps(barProps, frameW, barPropObjects, false);
+    t.done();
+  }, 0);
+}, "BarBrop objects of a nested Window");
+
+async_test(t => {
+  const openee = window.open("/common/blank.html"),
+        barProps = ["locationbar", "menubar", "personalbar", "scrollbars", "statusbar", "toolbar"],
+        barPropObjects = barProps.map(val => openee[val]);
+
+  // This is used to demonstrate that the Document is replaced while the global object (not the
+  // global this object) stays the same
+  openee.tiedToGlobalObject = openee.document;
+
+  assert_barProps(barPropObjects, true);
+  openee.onload = t.step_func(() => {
+    assert_own_property(openee, "tiedToGlobalObject");
+    assert_not_equals(openee.tiedToGlobalObject, openee.document);
+
+    assert_identical_barProps(barProps, openee, barPropObjects, true);
+
+    openee.onunload = t.step_func(() => {
+      assert_identical_barProps(barProps, openee, barPropObjects, true);
+      t.step_timeout(() => {
+        assert_identical_barProps(barProps, openee, barPropObjects, false);
+        t.done();
+      }, 0);
+    });
+
+    openee.close();
+    assert_identical_barProps(barProps, openee, barPropObjects, true);
+  });
+}, "BarProp objects of an auxiliary Window");