diff --git a/tests/cefclient/browser/osr_accessibility_helper.cc b/tests/cefclient/browser/osr_accessibility_helper.cc
index d829e5e7f..01fafc027 100644
--- a/tests/cefclient/browser/osr_accessibility_helper.cc
+++ b/tests/cefclient/browser/osr_accessibility_helper.cc
@@ -7,7 +7,7 @@
 
 namespace client {
 
-OsrAXTree::OsrAXTree() : parent_tree_id_(-1), root_node_id_(-1) {}
+OsrAXTree::OsrAXTree() : root_node_id_(-1) {}
 
 OsrAXNode* OsrAXTree::GetNode(int nodeId) const {
   auto result = node_map_.find(nodeId);
@@ -27,10 +27,9 @@ void OsrAXTree::AddNode(OsrAXNode* node) {
 
 void OsrAXTree::UpdateTreeData(CefRefPtr<CefDictionaryValue> value) {
   if (value->HasKey("parent_tree_id")) {
-    parent_tree_id_ =
-        OsrAccessibilityHelper::CastToInt(value->GetValue("parent_tree_id"));
+    parent_tree_id_ = value->GetString("parent_tree_id");
   } else {
-    parent_tree_id_ = -1;
+    parent_tree_id_ = "";
   }
 
   // may also update following:
@@ -39,9 +38,7 @@ void OsrAXTree::UpdateTreeData(CefRefPtr<CefDictionaryValue> value) {
 
 OsrAccessibilityHelper::OsrAccessibilityHelper(CefRefPtr<CefValue> value,
                                                CefRefPtr<CefBrowser> browser)
-    : root_tree_id_(-1),
-      focused_tree_id_(-1),
-      focused_node_id_(-1),
+    : focused_node_id_(-1),
       browser_(browser) {
   UpdateAccessibilityTree(value);
 }
@@ -75,7 +72,7 @@ void OsrAccessibilityHelper::UpdateAccessibilityLocation(
         !locationChangeDict->HasKey("id")) {
       continue;
     }
-    int treeId = CastToInt(locationChangeDict->GetValue("ax_tree_id"));
+    CefString treeId = locationChangeDict->GetString("ax_tree_id");
     int nodeId = CastToInt(locationChangeDict->GetValue("id"));
 
     CefRefPtr<CefDictionaryValue> newLocationDict =
@@ -103,7 +100,7 @@ void OsrAccessibilityHelper::UpdateAccessibilityTree(
     return;
   }
 
-  int treeId = CastToInt(mainDict->GetValue("ax_tree_id"));
+  CefString treeId = mainDict->GetString("ax_tree_id");
   CefRefPtr<CefListValue> updatesList = mainDict->GetList("updates");
 
   size_t updatesCount = updatesList->GetSize();
@@ -130,7 +127,8 @@ OsrAXNode* OsrAccessibilityHelper::GetFocusedNode() const {
   return nullptr;
 }
 
-OsrAXNode* OsrAccessibilityHelper::GetTreeRootNode(int treeId) const {
+OsrAXNode* OsrAccessibilityHelper::GetTreeRootNode(
+    const CefString& treeId) const {
   auto tree = accessibility_node_map_.find(treeId);
   if (tree != accessibility_node_map_.end()) {
     return tree->second.GetNode(tree->second.GetRootNodeId());
@@ -140,7 +138,7 @@ OsrAXNode* OsrAccessibilityHelper::GetTreeRootNode(int treeId) const {
 }
 
 void OsrAccessibilityHelper::UpdateLayout(
-    int treeId,
+    const CefString& treeId,
     CefRefPtr<CefDictionaryValue> update) {
   if (!update) {
     return;
@@ -154,12 +152,12 @@ void OsrAccessibilityHelper::UpdateLayout(
     auto tree = accessibility_node_map_.find(treeId);
     if (tree != accessibility_node_map_.end()) {
       if (tree->second.GetRootNodeId() == nodeId) {
-        root_tree_id_ = -1;
+        root_tree_id_ = "";
         tree->second.SetRootNodeId(-1);
       }
     }
     if ((focused_tree_id_ == treeId) && (focused_node_id_ == nodeId)) {
-      UpdateFocusedNode(-1, -1);
+      UpdateFocusedNode("", -1);
     }
     OsrAXNode* node = GetNode(treeId, nodeId);
     DestroyNode(node);
@@ -172,11 +170,11 @@ void OsrAccessibilityHelper::UpdateLayout(
         update->GetDictionary("tree_data");
     auto& tree = accessibility_node_map_[treeId];
     tree.UpdateTreeData(tree_data);
-    if (tree.GetParentTreeId() == -1) {
+    if (tree.GetParentTreeId().empty()) {
       root_tree_id_ = treeId;
     }
     if (tree_data->HasKey("focus_id") && tree_data->HasKey("focused_tree_id")) {
-      UpdateFocusedNode(CastToInt(tree_data->GetValue("focused_tree_id")),
+      UpdateFocusedNode(tree_data->GetString("focused_tree_id"),
                         CastToInt(tree_data->GetValue("focus_id")));
     }
   }
@@ -212,7 +210,8 @@ void OsrAccessibilityHelper::UpdateLayout(
   }
 }
 
-void OsrAccessibilityHelper::UpdateFocusedNode(int treeId, int nodeId) {
+void OsrAccessibilityHelper::UpdateFocusedNode(const CefString& treeId,
+                                               int nodeId) {
   if ((focused_tree_id_ == treeId) && (focused_node_id_ == nodeId)) {
     return;
   }
@@ -228,13 +227,14 @@ void OsrAccessibilityHelper::UpdateFocusedNode(int treeId, int nodeId) {
 
 void OsrAccessibilityHelper::Reset() {
   accessibility_node_map_.clear();
-  root_tree_id_ = -1;
-  focused_tree_id_ = focused_node_id_ = -1;
+  root_tree_id_ = "";
+  focused_tree_id_ = "";
+  focused_node_id_ = -1;
 }
 
 void OsrAccessibilityHelper::DestroyNode(OsrAXNode* node) {
   if (node) {
-    int treeId = node->OsrAXTreeId();
+    CefString treeId = node->OsrAXTreeId();
     int numChilds = node->GetChildCount();
     if (numChilds > 0) {
       for (int i = 0; i < numChilds; i++) {
@@ -257,7 +257,8 @@ void OsrAccessibilityHelper::DestroyNode(OsrAXNode* node) {
   }
 }
 
-OsrAXNode* OsrAccessibilityHelper::GetNode(int treeId, int nodeId) const {
+OsrAXNode* OsrAccessibilityHelper::GetNode(const CefString& treeId,
+                                           int nodeId) const {
   auto tree = accessibility_node_map_.find(treeId);
   if (tree != accessibility_node_map_.end()) {
     return tree->second.GetNode(nodeId);
diff --git a/tests/cefclient/browser/osr_accessibility_helper.h b/tests/cefclient/browser/osr_accessibility_helper.h
index 61db6d8c6..83f271e41 100644
--- a/tests/cefclient/browser/osr_accessibility_helper.h
+++ b/tests/cefclient/browser/osr_accessibility_helper.h
@@ -21,12 +21,12 @@ class OsrAXTree {
   void EraseNode(int nodeId);
   void UpdateTreeData(CefRefPtr<CefDictionaryValue> value);
   void AddNode(OsrAXNode* node);
-  int GetParentTreeId() const { return parent_tree_id_; }
+  const CefString& GetParentTreeId() const { return parent_tree_id_; }
   int GetRootNodeId() const { return root_node_id_; }
   void SetRootNodeId(int nodeId) { root_node_id_ = nodeId; }
 
  private:
-  int parent_tree_id_;
+  CefString parent_tree_id_;
   int root_node_id_;
   std::map<int, OsrAXNode*> node_map_;
 };
@@ -53,26 +53,27 @@ class OsrAccessibilityHelper {
 
   CefRefPtr<CefBrowser> GetBrowser() const { return browser_; }
 
-  OsrAXNode* GetNode(int treeId, int nodeId) const;
+  OsrAXNode* GetNode(const CefString& treeId, int nodeId) const;
 
-  OsrAXNode* GetTreeRootNode(int treeId) const;
+  OsrAXNode* GetTreeRootNode(const CefString& treeId) const;
 
   static int CastToInt(CefRefPtr<CefValue> value);
 
  private:
   void Reset();
 
-  void UpdateLayout(int treeId, CefRefPtr<CefDictionaryValue> update);
+  void UpdateLayout(const CefString& treeId,
+                    CefRefPtr<CefDictionaryValue> update);
 
-  void UpdateFocusedNode(int treeId, int nodeId);
+  void UpdateFocusedNode(const CefString& treeId, int nodeId);
 
   // Destroy the node and remove from Map
   void DestroyNode(OsrAXNode* node);
-  int root_tree_id_;
-  int focused_tree_id_;
+  CefString root_tree_id_;
+  CefString focused_tree_id_;
   int focused_node_id_;
   CefRefPtr<CefBrowser> browser_;
-  std::map<int, OsrAXTree> accessibility_node_map_;
+  std::map<CefString, OsrAXTree> accessibility_node_map_;
 };
 
 }  // namespace client
diff --git a/tests/cefclient/browser/osr_accessibility_node.cc b/tests/cefclient/browser/osr_accessibility_node.cc
index a7c14046e..befa25ff0 100644
--- a/tests/cefclient/browser/osr_accessibility_node.cc
+++ b/tests/cefclient/browser/osr_accessibility_node.cc
@@ -11,13 +11,12 @@
 
 namespace client {
 
-OsrAXNode::OsrAXNode(int treeId,
+OsrAXNode::OsrAXNode(const CefString& treeId,
                      int nodeId,
                      CefRefPtr<CefDictionaryValue> value,
                      OsrAccessibilityHelper* helper)
     : tree_id_(treeId),
       node_id_(nodeId),
-      child_tree_id_(-1),
       platform_accessibility_(nullptr),
       parent_(nullptr),
       offset_container_id_(-1),
@@ -68,7 +67,7 @@ void OsrAXNode::UpdateValue(CefRefPtr<CefDictionaryValue> value) {
   }
   // Update attributes
   if (value->HasKey("attributes")) {
-    child_tree_id_ = -1;
+    child_tree_id_ = "";
 
     attributes_ = value->GetDictionary("attributes");
 
@@ -84,8 +83,7 @@ void OsrAXNode::UpdateValue(CefRefPtr<CefDictionaryValue> value) {
     }
 
     if (attributes_ && attributes_->HasKey("childTreeId")) {
-      child_tree_id_ = OsrAccessibilityHelper::CastToInt(
-          attributes_->GetValue("childTreeId"));
+      child_tree_id_ = attributes_->GetString("childTreeId");
     }
     if (attributes_ && attributes_->HasKey("name"))
       name_ = attributes_->GetString("name");
@@ -139,7 +137,7 @@ CefRect OsrAXNode::AxLocation() const {
 
 int OsrAXNode::GetChildCount() const {
   int count = static_cast<int>(child_ids_.size());
-  if (child_tree_id_ >= 0) {
+  if (!child_tree_id_.empty()) {
     OsrAXNode* childTreeRootNode =
         accessibility_helper_->GetTreeRootNode(child_tree_id_);
     if (childTreeRootNode) {
@@ -153,7 +151,7 @@ OsrAXNode* OsrAXNode::ChildAtIndex(int index) const {
   int count = static_cast<int>(child_ids_.size());
   if (index < count)
     return accessibility_helper_->GetNode(OsrAXTreeId(), child_ids_[index]);
-  if ((index == count) && (child_tree_id_ >= 0)) {
+  if ((index == count) && (!child_tree_id_.empty())) {
     OsrAXNode* childTreeRootNode =
         accessibility_helper_->GetTreeRootNode(child_tree_id_);
     if (childTreeRootNode) {
@@ -165,7 +163,7 @@ OsrAXNode* OsrAXNode::ChildAtIndex(int index) const {
 }
 
 // Create and return the platform specific OsrAXNode Object
-OsrAXNode* OsrAXNode::CreateNode(int treeId,
+OsrAXNode* OsrAXNode::CreateNode(const CefString& treeId,
                                  int nodeId,
                                  CefRefPtr<CefDictionaryValue> value,
                                  OsrAccessibilityHelper* helper) {
diff --git a/tests/cefclient/browser/osr_accessibility_node.h b/tests/cefclient/browser/osr_accessibility_node.h
index 9cb72273a..ece83c018 100644
--- a/tests/cefclient/browser/osr_accessibility_node.h
+++ b/tests/cefclient/browser/osr_accessibility_node.h
@@ -40,7 +40,7 @@ class OsrAccessibilityHelper;
 class OsrAXNode {
  public:
   // Create and return the platform specific OsrAXNode Object.
-  static OsrAXNode* CreateNode(int treeId,
+  static OsrAXNode* CreateNode(const CefString& treeId,
                                int nodeId,
                                CefRefPtr<CefDictionaryValue> value,
                                OsrAccessibilityHelper* helper);
@@ -77,7 +77,7 @@ class OsrAXNode {
 
   const CefString& AxRole() const { return role_; }
 
-  int OsrAXTreeId() const { return tree_id_; }
+  const CefString& OsrAXTreeId() const { return tree_id_; }
 
   int OsrAXNodeId() const { return node_id_; }
 
@@ -96,14 +96,14 @@ class OsrAXNode {
   void SetParent(OsrAXNode* parent);
 
  protected:
-  OsrAXNode(int treeId,
+  OsrAXNode(const CefString& treeId,
             int nodeId,
             CefRefPtr<CefDictionaryValue> value,
             OsrAccessibilityHelper* helper);
 
-  int tree_id_;
+  CefString tree_id_;
   int node_id_;
-  int child_tree_id_;
+  CefString child_tree_id_;
   CefString role_;
   CefString value_;
   CefString name_;