[DevTools] New harness for inspector-protocol layout tests

third_party/WebKit/LayoutTests/inspector-protocol/accessibility/accessibility-modal.js

+(async function() {
+  let {page, session, Protocol} = await InspectorTest.startHTML(`
+    <dialog data-dump id='modal'>
+      <div data-dump role='button' aria-modal='true'>
+      </div>
+      <div data-dump role='dialog' aria-modal='false'>
+      </div>
+      <div data-dump role='dialog' aria-modal='true'>
+      </div>
+      <div data-dump role='alertdialog' aria-modal='true'>
+      </div>
+      <dialog data-dump>Closed Dialog</dialog>
+      <dialog data-dump open>Open Dialog</dialog>
+    </dialog>
+  `, '');
+
+  (await InspectorTest.loadScript('../resources/accessibility-dumpAccessibilityNodes.js'))(session);
+
+  await session.evaluate('document.getElementById("modal").showModal();');
+  var msg = await Protocol.DOM.getDocument();
+  InspectorTest.dumpAccessibilityNodesBySelectorAndCompleteTest('[data-dump]', false, msg);
+})();