Update chromecast automation code

Updates automation code to keep up to date with recent
refactoring in chrome tree.

Bug: None
Test: Manual
Change-Id: I56d77ce1a891b155d9374aed9b9690c2782159df
Reviewed-on: https://chromium-review.googlesource.com/c/1315702Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Luke Halliwell <halliwell@chromium.org>
Commit-Queue: Randy Rossi <rmrossi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606106}

chrome/renderer/extensions/automation_internal_custom_bindings.cc

@@ -374,8 +374,7 @@ class NodeIDPlusStringBoolWrapper
 class AutomationMessageFilter : public IPC::MessageFilter {
  public:
   explicit AutomationMessageFilter(AutomationInternalCustomBindings* owner)
-      : owner_(owner),
-        removed_(false) {
+      : owner_(owner), removed_(false) {
     DCHECK(owner);
     content::RenderThread::Get()->AddFilter(this);
     task_runner_ = base::ThreadTaskRunnerHandle::Get();
@@ -390,28 +389,23 @@ class AutomationMessageFilter : public IPC::MessageFilter {
   bool OnMessageReceived(const IPC::Message& message) override {
     task_runner_->PostTask(
         FROM_HERE,
-        base::Bind(
-            &AutomationMessageFilter::OnMessageReceivedOnRenderThread,
-            this, message));
+        base::Bind(&AutomationMessageFilter::OnMessageReceivedOnRenderThread,
+                   this, message));
 
     // Always return false in case there are multiple
     // AutomationInternalCustomBindings instances attached to the same thread.
     return false;
   }
 
-  void OnFilterRemoved() override {
-    removed_ = true;
-  }
+  void OnFilterRemoved() override { removed_ = true; }
 
-private:
+ private:
   void OnMessageReceivedOnRenderThread(const IPC::Message& message) {
     if (owner_)
       owner_->OnMessageReceived(message);
   }
 
-  ~AutomationMessageFilter() override {
-    Remove();
-  }
+  ~AutomationMessageFilter() override { Remove(); }
 
   void Remove() {
     if (!removed_) {
@@ -441,8 +435,8 @@ AutomationInternalCustomBindings::AutomationInternalCustomBindings(
   if (context && context->extension()) {
     const GURL background_page_url =
         extensions::BackgroundInfo::GetBackgroundURL(context->extension());
-    should_ignore_context_ = background_page_url != "" &&
-        background_page_url != context->url();
+    should_ignore_context_ =
+        background_page_url != "" && background_page_url != context->url();
   }
 }
 
@@ -466,7 +460,7 @@ void AutomationInternalCustomBindings::AddRoutes() {
   ROUTE_FUNCTION(GetFocus);
   ROUTE_FUNCTION(GetHtmlAttributes);
   ROUTE_FUNCTION(GetState);
-  #undef ROUTE_FUNCTION
+#undef ROUTE_FUNCTION
 
   // Bindings that take a Tree ID and return a property of the tree.
 
@@ -1637,8 +1631,8 @@ bool AutomationInternalCustomBindings::SendTreeChangeEvent(
 
   bool has_filter = false;
   if (tree_change_observer_overall_filter_ &
-      (1 <<
-       api::automation::TREE_CHANGE_OBSERVER_FILTER_LIVEREGIONTREECHANGES)) {
+      (1
+       << api::automation::TREE_CHANGE_OBSERVER_FILTER_LIVEREGIONTREECHANGES)) {
     if (node->data().HasStringAttribute(
             ax::mojom::StringAttribute::kContainerLiveStatus) ||
         node->data().role == ax::mojom::Role::kAlert ||

chromecast/common/extensions_api/automation.idl

@@ -178,6 +178,7 @@
     imageMap,
     inlineTextBox,
     inputTime,
+    keyboard,
     labelText,
     layoutTable,
     layoutTableCell,
@@ -191,7 +192,6 @@
     listBoxOption,
     listItem,
     listMarker,
-    locationBar,
     log,
     main,
     mark,
@@ -356,9 +356,11 @@
     uninitialized,
     attribute,
     attributeExplicitlyEmpty,
+    caption,
     contents,
     placeholder,
     relatedElement,
+    title,
     value
   };
 
@@ -576,6 +578,9 @@
     // applicable
     AutomationNode? activeDescendant;
 
+    // Reverse relationship for active descendant.
+    AutomationNode[]? activeDescendantFor;
+
     // The target of an in-page link.
     AutomationNode? inPageLinkTarget;
 
@@ -604,10 +609,10 @@
     AutomationNode[]? labelFor;
 
     // The column header nodes for a table cell.
-    AutomationNode? tableCellColumnHeaders;
+    AutomationNode[]? tableCellColumnHeaders;
 
     // The row header nodes for a table cell.
-    AutomationNode? tableCellRowHeaders;
+    AutomationNode[]? tableCellRowHeaders;
 
     // An array of standard actions available on this node.
     ActionType[]? standardActions;
@@ -652,6 +657,9 @@
     long? scrollYMin;
     long? scrollYMax;
 
+    // Indicates whether this node is scrollable.
+    boolean? scrollable;
+
     //
     // Editable text field attributes.
     //
@@ -667,9 +675,6 @@
     // The input type, like email or number.
     DOMString? textInputType;
 
-    // An array of indexes of the break between lines in editable text.
-    long[] lineBreaks;
-
     // An array of indexes of the start position of each text marker.
     long[] markerStarts;
 
@@ -855,6 +860,9 @@
     // 'false' | 'true' | 'mixed'
     DOMString? checked;
 
+    // The inner html of this element. Only populated for math content.
+    DOMString? innerHtml;
+
     // The RGBA foreground color of this subtree, as an integer.
     long? color;
 

chromecast/common/extensions_api/automation_internal.idl

@@ -103,7 +103,7 @@ namespace automationInternal {
 
   // Returns the accessibility tree id of the web contents who's accessibility
   // was enabled using enableTab().
-  callback EnableTabCallback = void(long tree_id);
+  callback EnableTabCallback = void(DOMString tree_id);
 
   // Callback called when enableDesktop() returns.
   callback EnableDesktopCallback = void();
@@ -119,7 +119,7 @@ namespace automationInternal {
                           EnableTabCallback callback);
 
     // Enable automation of the frame with the given tree id.
-    static void enableFrame(DOMString treeId);
+    static void enableFrame(DOMString tree_id);
 
     // Enables desktop automation.
     static void enableDesktop(EnableDesktopCallback callback);
@@ -144,7 +144,7 @@ namespace automationInternal {
                              long nodeID,
                              DOMString changeType);
 
-    static void onChildTreeID(DOMString treeID, long nodeID);
+    static void onChildTreeID(DOMString treeID);
 
     static void onNodesRemoved(DOMString treeID, long[] nodeIDs);
 

chromecast/renderer/extensions/automation_ax_tree_wrapper.cc

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "base/no_destructor.h"
 #include "chromecast/common/extensions_api/cast_extension_messages.h"
 #include "chromecast/renderer/extensions/automation_internal_custom_bindings.h"
 #include "ui/accessibility/ax_node.h"
@@ -11,6 +12,12 @@ namespace cast {
 
 namespace {
 
+std::map<ui::AXTreeID, AutomationAXTreeWrapper*>& GetChildTreeIDReverseMap() {
+  static base::NoDestructor<std::map<ui::AXTreeID, AutomationAXTreeWrapper*>>
+      child_tree_id_reverse_map;
+  return *child_tree_id_reverse_map;
+}
+
 // Convert from ax::mojom::Event to api::automation::EventType.
 api::automation::EventType ToAutomationEvent(ax::mojom::Event event_type) {
   switch (event_type) {
@@ -193,7 +200,7 @@ api::automation::EventType ToAutomationEvent(
 AutomationAXTreeWrapper::AutomationAXTreeWrapper(
     ui::AXTreeID tree_id,
     AutomationInternalCustomBindings* owner)
-    : tree_id_(tree_id), host_node_id_(-1), owner_(owner) {
+    : tree_id_(tree_id), owner_(owner) {
   // We have to initialize AXEventGenerator here - we can't do it in the
   // initializer list because AXTree hasn't been initialized yet at that point.
   SetTree(&tree_);
@@ -205,12 +212,32 @@ AutomationAXTreeWrapper::~AutomationAXTreeWrapper() {
   tree_.SetDelegate(nullptr);
 }
 
+// static
+AutomationAXTreeWrapper* AutomationAXTreeWrapper::GetParentOfTreeId(
+    ui::AXTreeID tree_id) {
+  std::map<ui::AXTreeID, AutomationAXTreeWrapper*>& child_tree_id_reverse_map =
+      GetChildTreeIDReverseMap();
+  const auto& iter = child_tree_id_reverse_map.find(tree_id);
+  if (iter != child_tree_id_reverse_map.end())
+    return iter->second;
+
+  return nullptr;
+}
+
 bool AutomationAXTreeWrapper::OnAccessibilityEvents(
     const ExtensionMsg_AccessibilityEventBundleParams& event_bundle,
     bool is_active_profile) {
+  std::map<ui::AXTreeID, AutomationAXTreeWrapper*>& child_tree_id_reverse_map =
+      GetChildTreeIDReverseMap();
+  for (const ui::AXTreeID& tree_id : tree_.GetAllChildTreeIds()) {
+    DCHECK_EQ(child_tree_id_reverse_map[tree_id], this);
+    child_tree_id_reverse_map.erase(tree_id);
+  }
+
   for (const auto& update : event_bundle.updates) {
     set_event_from(update.event_from);
     deleted_node_ids_.clear();
+    did_send_tree_change_during_unserialization_ = false;
 
     if (!tree_.Unserialize(update))
       return false;
@@ -218,7 +245,7 @@ bool AutomationAXTreeWrapper::OnAccessibilityEvents(
     if (is_active_profile) {
       owner_->SendNodesRemovedEvent(&tree_, deleted_node_ids_);
 
-      if (update.nodes.size()) {
+      if (update.nodes.size() && did_send_tree_change_during_unserialization_) {
         ui::AXNode* target = tree_.GetFromId(update.nodes[0].id);
         if (target) {
           owner_->SendTreeChangeEvent(
@@ -229,12 +256,32 @@ bool AutomationAXTreeWrapper::OnAccessibilityEvents(
     }
   }
 
+  for (const ui::AXTreeID& tree_id : tree_.GetAllChildTreeIds()) {
+    DCHECK(!base::ContainsKey(child_tree_id_reverse_map, tree_id));
+    child_tree_id_reverse_map.insert(std::make_pair(tree_id, this));
+  }
+
   // Exit early if this isn't the active profile.
   if (!is_active_profile)
     return true;
 
+  // Send all blur and focus events first. This ensures we correctly dispatch
+  // these events, which gets re-targetted in the js bindings and ensures it
+  // receives the correct value for |event_from|.
+  for (const auto& event : event_bundle.events) {
+    if (event.event_type != ax::mojom::Event::kFocus &&
+        event.event_type != ax::mojom::Event::kBlur)
+      continue;
+
+    api::automation::EventType automation_event_type =
+        ToAutomationEvent(event.event_type);
+    owner_->SendAutomationEvent(event_bundle.tree_id,
+                                event_bundle.mouse_location, event,
+                                automation_event_type);
+  }
+
   // Send auto-generated AXEventGenerator events.
-  for (auto targeted_event : *this) {
+  for (const auto& targeted_event : *this) {
     api::automation::EventType event_type =
         ToAutomationEvent(targeted_event.event_params.event);
     if (IsEventTypeHandledByAXEventGenerator(event_type)) {
@@ -248,7 +295,11 @@ bool AutomationAXTreeWrapper::OnAccessibilityEvents(
   }
   ClearEvents();
 
-  for (auto event : event_bundle.events) {
+  for (const auto& event : event_bundle.events) {
+    if (event.event_type == ax::mojom::Event::kFocus ||
+        event.event_type == ax::mojom::Event::kBlur)
+      continue;
+
     api::automation::EventType automation_event_type =
         ToAutomationEvent(event.event_type);
 
@@ -277,8 +328,8 @@ void AutomationAXTreeWrapper::OnNodeDataWillChange(
 void AutomationAXTreeWrapper::OnNodeWillBeDeleted(ui::AXTree* tree,
                                                   ui::AXNode* node) {
   AXEventGenerator::OnNodeWillBeDeleted(tree, node);
-  owner_->SendTreeChangeEvent(api::automation::TREE_CHANGE_TYPE_NODEREMOVED,
-                              tree, node);
+  did_send_tree_change_during_unserialization_ |= owner_->SendTreeChangeEvent(
+      api::automation::TREE_CHANGE_TYPE_NODEREMOVED, tree, node);
   deleted_node_ids_.push_back(node->id());
 }
 
@@ -292,16 +343,19 @@ void AutomationAXTreeWrapper::OnAtomicUpdateFinished(
     ui::AXNode* node = change.node;
     switch (change.type) {
       case NODE_CREATED:
-        owner_->SendTreeChangeEvent(
-            api::automation::TREE_CHANGE_TYPE_NODECREATED, tree, node);
+        did_send_tree_change_during_unserialization_ |=
+            owner_->SendTreeChangeEvent(
+                api::automation::TREE_CHANGE_TYPE_NODECREATED, tree, node);
         break;
       case SUBTREE_CREATED:
-        owner_->SendTreeChangeEvent(
-            api::automation::TREE_CHANGE_TYPE_SUBTREECREATED, tree, node);
+        did_send_tree_change_during_unserialization_ |=
+            owner_->SendTreeChangeEvent(
+                api::automation::TREE_CHANGE_TYPE_SUBTREECREATED, tree, node);
         break;
       case NODE_CHANGED:
-        owner_->SendTreeChangeEvent(
-            api::automation::TREE_CHANGE_TYPE_NODECHANGED, tree, node);
+        did_send_tree_change_during_unserialization_ |=
+            owner_->SendTreeChangeEvent(
+                api::automation::TREE_CHANGE_TYPE_NODECHANGED, tree, node);
         break;
       // Unhandled.
       case NODE_REPARENTED:
@@ -311,8 +365,9 @@ void AutomationAXTreeWrapper::OnAtomicUpdateFinished(
   }
 
   for (int id : text_changed_node_ids_) {
-    owner_->SendTreeChangeEvent(api::automation::TREE_CHANGE_TYPE_TEXTCHANGED,
-                                tree, tree->GetFromId(id));
+    did_send_tree_change_during_unserialization_ |= owner_->SendTreeChangeEvent(
+        api::automation::TREE_CHANGE_TYPE_TEXTCHANGED, tree,
+        tree->GetFromId(id));
   }
   text_changed_node_ids_.clear();
 }
@@ -324,6 +379,7 @@ bool AutomationAXTreeWrapper::IsEventTypeHandledByAXEventGenerator(
     case api::automation::EVENT_TYPE_ACTIVEDESCENDANTCHANGED:
     case api::automation::EVENT_TYPE_ARIAATTRIBUTECHANGED:
     case api::automation::EVENT_TYPE_CHECKEDSTATECHANGED:
+    case api::automation::EVENT_TYPE_CHILDRENCHANGED:
     case api::automation::EVENT_TYPE_DOCUMENTSELECTIONCHANGED:
     case api::automation::EVENT_TYPE_DOCUMENTTITLECHANGED:
     case api::automation::EVENT_TYPE_EXPANDEDCHANGED:
@@ -332,6 +388,9 @@ bool AutomationAXTreeWrapper::IsEventTypeHandledByAXEventGenerator(
     case api::automation::EVENT_TYPE_LIVEREGIONCREATED:
     case api::automation::EVENT_TYPE_LOADCOMPLETE:
     case api::automation::EVENT_TYPE_LOADSTART:
+    case api::automation::EVENT_TYPE_ROWCOLLAPSED:
+    case api::automation::EVENT_TYPE_ROWCOUNTCHANGED:
+    case api::automation::EVENT_TYPE_ROWEXPANDED:
     case api::automation::EVENT_TYPE_SCROLLPOSITIONCHANGED:
     case api::automation::EVENT_TYPE_SELECTEDCHILDRENCHANGED:
       return true;
@@ -365,24 +424,20 @@ bool AutomationAXTreeWrapper::IsEventTypeHandledByAXEventGenerator(
     case api::automation::EVENT_TYPE_MOUSEMOVED:
     case api::automation::EVENT_TYPE_MOUSEPRESSED:
     case api::automation::EVENT_TYPE_MOUSERELEASED:
+    case api::automation::EVENT_TYPE_SCROLLEDTOANCHOR:
     case api::automation::EVENT_TYPE_WINDOWACTIVATED:
     case api::automation::EVENT_TYPE_WINDOWDEACTIVATED:
-    case api::automation::EVENT_TYPE_SCROLLEDTOANCHOR:
       return false;
 
     // These events might need to be migrated to AXEventGenerator.
     case api::automation::EVENT_TYPE_ALERT:
     case api::automation::EVENT_TYPE_BLUR:
-    case api::automation::EVENT_TYPE_CHILDRENCHANGED:
     case api::automation::EVENT_TYPE_FOCUS:
     case api::automation::EVENT_TYPE_IMAGEFRAMEUPDATED:
     case api::automation::EVENT_TYPE_LOCATIONCHANGED:
     case api::automation::EVENT_TYPE_MENUEND:
     case api::automation::EVENT_TYPE_MENULISTITEMSELECTED:
     case api::automation::EVENT_TYPE_MENUSTART:
-    case api::automation::EVENT_TYPE_ROWCOLLAPSED:
-    case api::automation::EVENT_TYPE_ROWCOUNTCHANGED:
-    case api::automation::EVENT_TYPE_ROWEXPANDED:
     case api::automation::EVENT_TYPE_SELECTION:
     case api::automation::EVENT_TYPE_TEXTCHANGED:
     case api::automation::EVENT_TYPE_TEXTSELECTIONCHANGED:

chromecast/renderer/extensions/automation_ax_tree_wrapper.h

@@ -23,16 +23,14 @@ class AutomationAXTreeWrapper : public ui::AXEventGenerator {
                           AutomationInternalCustomBindings* owner);
   ~AutomationAXTreeWrapper() override;
 
+  // Returns the AutomationAXTreeWrapper that lists |tree_id| as one of its
+  // child trees, if any.
+  static AutomationAXTreeWrapper* GetParentOfTreeId(ui::AXTreeID tree_id);
+
   ui::AXTreeID tree_id() const { return tree_id_; }
   ui::AXTree* tree() { return &tree_; }
   AutomationInternalCustomBindings* owner() { return owner_; }
 
-  // The host node ID is the node ID of the parent node in the parent tree.
-  // For example, the host node ID of a web area of a child frame is the
-  // ID of the <iframe> element in its parent frame.
-  int32_t host_node_id() const { return host_node_id_; }
-  void set_host_node_id(int32_t id) { host_node_id_ = id; }
-
   // Called by AutomationInternalCustomBindings::OnAccessibilityEvents on
   // the AutomationAXTreeWrapper instance for the correct tree corresponding
   // to this event. Unserializes the tree update and calls back to
@@ -57,12 +55,15 @@ class AutomationAXTreeWrapper : public ui::AXEventGenerator {
   bool IsEventTypeHandledByAXEventGenerator(api::automation::EventType) const;
 
   ui::AXTreeID tree_id_;
-  int32_t host_node_id_;
   ui::AXTree tree_;
   AutomationInternalCustomBindings* owner_;
   std::vector<int> deleted_node_ids_;
   std::vector<int> text_changed_node_ids_;
 
+  // Tracks whether a tree change event was sent during unserialization. Tree
+  // changes outside of unserialization do not get reflected here. The value is
+  // reset after unserialization.
+  bool did_send_tree_change_during_unserialization_ = false;
   DISALLOW_COPY_AND_ASSIGN(AutomationAXTreeWrapper);
 };
 

chromecast/renderer/extensions/automation_internal_custom_bindings.h

@@ -53,14 +53,26 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
   void OnMessageReceived(const IPC::Message& message);
 
   AutomationAXTreeWrapper* GetAutomationAXTreeWrapperFromTreeID(
-      ui::AXTreeID tree_id);
+      ui::AXTreeID tree_id) const;
 
   // Given a tree (|in_out_tree_wrapper|) and a node, returns the parent.
   // If |node| is the root of its tree, the return value will be the host
   // node of the parent tree and |in_out_tree_wrapper| will be updated to
   // point to that parent tree.
   ui::AXNode* GetParent(ui::AXNode* node,
-                        AutomationAXTreeWrapper** in_out_tree_wrapper);
+                        AutomationAXTreeWrapper** in_out_tree_wrapper) const;
+
+  // Gets the root of a node's child tree and adjusts incoming arguments
+  // accordingly. Returns false if no adjustments were made.
+  bool GetRootOfChildTree(ui::AXNode** in_out_node,
+                          AutomationAXTreeWrapper** in_out_tree_wrapper) const;
+
+  ui::AXNode* GetNextInTreeOrder(
+      ui::AXNode* start,
+      AutomationAXTreeWrapper** in_out_tree_wrapper) const;
+  ui::AXNode* GetPreviousInTreeOrder(
+      ui::AXNode* start,
+      AutomationAXTreeWrapper** in_out_tree_wrapper) const;
 
   ScriptContext* context() const {
     return ObjectBackedNativeHandler::context();
@@ -69,12 +81,12 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
   float GetDeviceScaleFactor() const;
 
   void SendNodesRemovedEvent(ui::AXTree* tree, const std::vector<int>& ids);
-  void SendTreeChangeEvent(api::automation::TreeChangeType change_type,
+  bool SendTreeChangeEvent(api::automation::TreeChangeType change_type,
                            ui::AXTree* tree,
                            ui::AXNode* node);
   void SendAutomationEvent(ui::AXTreeID tree_id,
                            const gfx::Point& mouse_location,
-                           ui::AXEvent& event,
+                           const ui::AXEvent& event,
                            api::automation::EventType event_type);
 
  private:
@@ -98,7 +110,7 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
 
   // Called when an accessibility tree is destroyed and needs to be
   // removed from our cache.
-  // Args: int ax_tree_id
+  // Args: string ax_tree_id
   void DestroyAccessibilityTree(
       const v8::FunctionCallbackInfo<v8::Value>& args);
 
@@ -124,11 +136,10 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
 
   void RouteNodeIDFunction(
       const std::string& name,
-      void (*callback)(v8::Isolate* isolate,
-                       v8::ReturnValue<v8::Value> result,
-                       AutomationAXTreeWrapper* tree_wrapper,
-                       ui::AXNode* node));
-
+      std::function<void(v8::Isolate* isolate,
+                         v8::ReturnValue<v8::Value> result,
+                         AutomationAXTreeWrapper* tree_wrapper,
+                         ui::AXNode* node)> callback);
   void RouteNodeIDPlusAttributeFunction(
       const std::string& name,
       void (*callback)(v8::Isolate* isolate,
@@ -144,19 +155,27 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
                        ui::AXNode* node,
                        int start,
                        int end));
+  void RouteNodeIDPlusStringBoolFunction(
+      const std::string& name,
+      std::function<void(v8::Isolate* isolate,
+                         v8::ReturnValue<v8::Value> result,
+                         AutomationAXTreeWrapper* tree_wrapper,
+                         ui::AXNode* node,
+                         const std::string& strVal,
+                         bool boolVal)> callback);
 
   //
   // Access the cached accessibility trees and properties of their nodes.
   //
 
-  // Args: int ax_tree_id, int node_id, Returns: int child_id.
+  // Args: string ax_tree_id, int node_id, Returns: int child_id.
   void GetChildIDAtIndex(const v8::FunctionCallbackInfo<v8::Value>& args);
 
-  // Args: int ax_tree_id, int node_id
+  // Args: string ax_tree_id, int node_id
   // Returns: JS object with a map from html attribute key to value.
   void GetHtmlAttributes(const v8::FunctionCallbackInfo<v8::Value>& args);
 
-  // Args: int ax_tree_id, int node_id
+  // Args: string ax_tree_id, int node_id
   // Returns: JS object with a string key for each state flag that's set.
   void GetState(const v8::FunctionCallbackInfo<v8::Value>& args);
 
@@ -173,7 +192,7 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
 
   void UpdateOverallTreeChangeObserverFilter();
 
-  void SendChildTreeIDEvent(ui::AXTree* tree, ui::AXNode* node);
+  void SendChildTreeIDEvent(ui::AXTreeID child_tree_id);
 
   std::map<ui::AXTreeID, std::unique_ptr<AutomationAXTreeWrapper>>
       tree_id_to_tree_wrapper_map_;

chromecast/renderer/resources/extensions/automation_custom_bindings.js

@@ -37,7 +37,7 @@ window.automationUtil = function() {};
 // TODO(aboxhall): Look into using WeakMap
 var idToCallback = {};
 
-var DESKTOP_TREE_ID = 0;
+var DESKTOP_TREE_ID = "0";
 
 automationUtil.storeTreeCallback = function(id, callback) {
   if (!callback)
@@ -198,14 +198,12 @@ automation.registerCustomHook(function(bindingsAPI) {
 
 });
 
-automationInternal.onChildTreeID.addListener(function(treeID,
-                                                      nodeID) {
-  var tree = AutomationRootNode.getOrCreate(treeID);
-  if (!tree)
-    return;
+automationInternal.onChildTreeID.addListener(function(childTreeId) {
+  var targetTree = AutomationRootNode.get(childTreeId);
 
-  var node = privates(tree).impl.get(nodeID);
-  if (!node)
+  // If the tree is already loded, or if we previously requested it be loaded
+  // (i.e. have a callback for it), don't try to do so again.
+  if (targetTree || idToCallback[childTreeId])
     return;
 
   // A WebView in the desktop tree has a different AX tree as its child.
@@ -213,30 +211,11 @@ automationInternal.onChildTreeID.addListener(function(treeID,
   // currently have cached, explicitly request that AX tree from the
   // browser process and set up a callback when it loads to attach that
   // tree as a child of this node and fire appropriate events.
-  var childTreeID = GetIntAttribute(treeID, nodeID, 'childTreeId');
-  if (!childTreeID)
-    return;
-
-  var subroot = AutomationRootNode.get(childTreeID);
-  if (!subroot || subroot.role == 'unknown') {
-    automationUtil.storeTreeCallback(childTreeID, function(root) {
-      // Return early if the root has already been attached.
-      if (root.parent)
-        return;
+  automationUtil.storeTreeCallback(childTreeId, function(root) {
+    privates(root).impl.dispatchEvent('loadComplete', 'page');
+  }, true);
 
-      privates(root).impl.setHostNode(node);
-
-      if (root.docLoaded) {
-        privates(root).impl.dispatchEvent('loadComplete', 'page');
-      }
-
-      privates(node).impl.dispatchEvent('childrenChanged', 'none');
-    });
-
-    automationInternal.enableFrame(childTreeID);
-  } else {
-    privates(subroot).impl.setHostNode(node);
-  }
+  automationInternal.enableFrame(childTreeId);
 });
 
 automationInternal.onTreeChange.addListener(function(observerID,
@@ -259,7 +238,7 @@ automationInternal.onTreeChange.addListener(function(observerID,
     observer({target: node, type: changeType});
   } catch (e) {
     exceptionHandler.handle('Error in tree change observer for ' +
-        treeChange.type, e);
+        changeType, e);
   }
 });