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chrome/renderer/resources/extensions/automation/automation_node.js

Index: chrome/renderer/resources/extensions/automation/automation_node.js
diff --git a/chrome/renderer/resources/extensions/automation/automation_node.js b/chrome/renderer/resources/extensions/automation/automation_node.js
index 357f192146963438d3dcb199b4fe57ff25cb7bac..d24c2d606ae22156a2ef6c011cc101c76aa3d861 100644
--- a/chrome/renderer/resources/extensions/automation/automation_node.js
+++ b/chrome/renderer/resources/extensions/automation/automation_node.js
@@ -307,18 +307,22 @@ AutomationNodeImpl.prototype = {
 
   get previousSibling() {
     var parent = this.parent;
+    if (!parent)
+      return undefined;
+    parent = privates(parent).impl;
     var indexInParent = GetIndexInParent(this.treeID, this.id);
-    if (parent && indexInParent > 0)
-      return parent.children[indexInParent - 1];
-    return undefined;
+    return this.rootImpl.get(
+        GetChildIDAtIndex(parent.treeID, parent.id, indexInParent - 1));
   },
 
   get nextSibling() {
     var parent = this.parent;
+    if (!parent)
+      return undefined;
+    parent = privates(parent).impl;
     var indexInParent = GetIndexInParent(this.treeID, this.id);
-    if (parent && indexInParent < parent.children.length)
-      return parent.children[indexInParent + 1];
-    return undefined;
+    return this.rootImpl.get(
+        GetChildIDAtIndex(parent.treeID, parent.id, indexInParent + 1));
   },
 
   doDefault: function() {