Add aria-owns DumpAccessibilityTree test and make it pass.

ui/accessibility/ax_tree_serializer.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_ACCESSIBILITY_AX_TREE_SERIALIZER_H_
 #define UI_ACCESSIBILITY_AX_TREE_SERIALIZER_H_
 
 #include <set>
 
 #include "base/containers/hash_tables.h"
@@ skipping 119 matching lines @@
   ClientTreeNode* ClientTreeNodeById(int32 id);
 
   // Delete the given client tree node and recursively delete all of its
   // descendants.
   void DeleteClientSubtree(ClientTreeNode* client_node);
 
   // Helper function, called recursively with each new node to serialize.
   void SerializeChangedNodes(AXSourceNode node,
                              AXTreeUpdate* out_update);
 
+  // Visit all of the descendants of |node| once.
+  void WalkAllDescendants(AXSourceNode node);
+
   // The tree source.
   AXTreeSource<AXSourceNode>* tree_;
 
   // Our representation of the client tree.
   ClientTreeNode* client_root_;
 
   // A map from IDs to nodes in the client tree.
   base::hash_map<int32, ClientTreeNode*> client_id_map_;
 };
 
@@ skipping 172 matching lines @@
         ClientTreeNode* client_lca = ClientTreeNodeById(tree_->GetId(lca));
         CHECK(client_lca);
         DeleteClientSubtree(client_lca);
       }
     }
   } while (need_delete);
 
   // Serialize from the LCA, or from the root if there isn't one.
   if (!tree_->IsValid(lca))
     lca = tree_->GetRoot();
+
+  // Work around flaky source trees where nodes don't figure out their
+  // correct parent/child relationships until you walk the whole tree once.
+  // Covered by this test in the content_browsertests suite:
+  //     DumpAccessibilityTreeTest.AccessibilityAriaOwns.
+  WalkAllDescendants(lca);
+
   SerializeChangedNodes(lca, out_update);
 }
 
 template<typename AXSourceNode>
 void AXTreeSerializer<AXSourceNode>::DeleteClientSubtree(AXSourceNode node) {
   ClientTreeNode* client_node = ClientTreeNodeById(tree_->GetId(node));
   if (client_node)
     DeleteClientSubtree(client_node);
 }
 
@@ skipping 123 matching lines @@
       SerializeChangedNodes(child, out_update);
     }
   }
 
   // Finally, update the child ids of this node to reflect the actual child
   // ids that were valid during serialization.
   out_update->nodes[serialized_node_index].child_ids.swap(
       actual_serialized_node_child_ids);
 }
 
+template<typename AXSourceNode>
+void AXTreeSerializer<AXSourceNode>::WalkAllDescendants(
+    AXSourceNode node) {
+  std::vector<AXSourceNode> children;
+  tree_->GetChildren(node, &children);
+  for (size_t i = 0; i < children.size(); ++i)
+    WalkAllDescendants(children[i]);
+}
+
 }  // namespace ui
 
 #endif  // UI_ACCESSIBILITY_AX_TREE_SERIALIZER_H_