Devtools: Correctly add ancestors in a11y tree for nodes with no AXNode

Bug: 1015529
Change-Id: I59c9991f3fd50582553883d4d27668960b4a6481
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1911064Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: Alice Boxhall <aboxhall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#715104}

third_party/blink/renderer/modules/accessibility/inspector_accessibility_agent.cc

@@ -572,7 +572,10 @@ void InspectorAccessibilityAgent::AddAncestors(
     std::unique_ptr<AXNode> parent_node_object = BuildProtocolAXObject(
         *ancestor, inspected_ax_object, true, nodes, cache);
     auto child_ids = std::make_unique<protocol::Array<AXNodeId>>();
+    if (child)
       child_ids->emplace_back(String::Number(child->AXObjectID()));
+    else
+      child_ids->emplace_back(String::Number(kIDForInspectedNodeWithNoAXNode));
     parent_node_object->setChildIds(std::move(child_ids));
     nodes->emplace_back(std::move(parent_node_object));
     child = ancestor;
@@ -653,16 +656,7 @@ void InspectorAccessibilityAgent::PopulateDOMNodeAncestors(
     return;
 
   // Populate parent and ancestors.
-  std::unique_ptr<AXNode> parent_node_object =
-      BuildProtocolAXObject(*parent_ax_object, nullptr, true, nodes, cache);
-  auto child_ids = std::make_unique<protocol::Array<AXNodeId>>();
-  child_ids->emplace_back(String::Number(kIDForInspectedNodeWithNoAXNode));
-  parent_node_object->setChildIds(std::move(child_ids));
-  nodes->emplace_back(std::move(parent_node_object));
-
-  AXObject* grandparent_ax_object = parent_ax_object->ParentObjectUnignored();
-  if (grandparent_ax_object)
-    AddAncestors(*grandparent_ax_object, nullptr, nodes, cache);
+  AddAncestors(*parent_ax_object, nullptr, nodes, cache);
 }
 
 std::unique_ptr<AXNode> InspectorAccessibilityAgent::BuildProtocolAXObject(

third_party/blink/web_tests/inspector-protocol/accessibility/accessibility-getTreeWithNoAXNode-expected.txt

+Tests that fetching the tree for a node without an AXNode functions correctly.
+
+WebArea
+  main
+    article
+      *Ignored
+{
+  "nodeId": "<string>",
+  "ignored": true,
+  "ignoredReasons": [
+    {
+      "name": "notRendered",
+      "value": {
+        "type": "boolean",
+        "value": true
+      }
+    }
+  ],
+  "role": {
+    "type": "internalRole",
+    "value": "Ignored"
+  },
+  "domNode": "div#hidden"
+}
+

third_party/blink/web_tests/inspector-protocol/accessibility/accessibility-getTreeWithNoAXNode.js

+(async function(testRunner) {
+  var {page, session, dp} = await testRunner.startHTML(`
+    <main>
+    <article>
+    <div id="hidden" style="display: none">hidden div</div>
+    </article>
+    </main>
+  `, 'Tests that fetching the tree for a node without an AXNode functions correctly.');
+
+  var dumpAccessibilityNodesBySelectorAndCompleteTest =
+      (await testRunner.loadScript('../resources/accessibility-dumpAccessibilityNodes.js'))(testRunner, session);
+
+  var msg = await dp.DOM.getDocument();
+  dumpAccessibilityNodesBySelectorAndCompleteTest('#hidden', true, msg);
+})