Support chrome.automation.getFocus on non-Aura platforms

R=dmazzoni@chromium.org

Test: manual; on Mac, verify chrome.automation.getFocus returns the correct value.
Change-Id: Iff9665c613ebf55920e7bf5afac2033b5abceeda
AX-Relnotes: n/a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2610925
Commit-Queue: David Tseng <dtseng@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#840843}

extensions/renderer/api/automation/automation_internal_custom_bindings.cc

@@ -675,6 +675,7 @@ void AutomationInternalCustomBindings::AddRoutes() {
   ROUTE_FUNCTION(GetState);
   ROUTE_FUNCTION(CreateAutomationPosition);
   ROUTE_FUNCTION(GetAccessibilityFocus);
+  ROUTE_FUNCTION(SetDesktopID);
 #undef ROUTE_FUNCTION
 
   // Bindings that take a Tree ID and return a property of the tree.
@@ -1913,26 +1914,33 @@ bool AutomationInternalCustomBindings::GetFocusInternal(
 
 void AutomationInternalCustomBindings::GetFocus(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
-  if (args.Length() != 1 || !args[0]->IsString()) {
+  if (args.Length() != 0) {
     ThrowInvalidArgumentsException(this);
     return;
   }
 
-  ui::AXTreeID tree_id = ui::AXTreeID::FromString(
-      *v8::String::Utf8Value(args.GetIsolate(), args[0]));
-  AutomationAXTreeWrapper* tree_wrapper =
-      GetAutomationAXTreeWrapperFromTreeID(tree_id);
-  if (!tree_wrapper)
-    return;
-
-  AutomationAXTreeWrapper* focused_tree_wrapper = nullptr;
+  AutomationAXTreeWrapper* desktop_tree =
+      GetAutomationAXTreeWrapperFromTreeID(desktop_tree_id_);
+  AutomationAXTreeWrapper* focused_wrapper = nullptr;
   ui::AXNode* focused_node = nullptr;
-  if (!GetFocusInternal(tree_wrapper, &focused_tree_wrapper, &focused_node))
+  if (desktop_tree &&
+      !GetFocusInternal(desktop_tree, &focused_wrapper, &focused_node))
     return;
 
+  if (!desktop_tree) {
+    focused_wrapper = GetAutomationAXTreeWrapperFromTreeID(focus_tree_id_);
+    if (!focused_wrapper)
+      return;
+
+    focused_node = focused_wrapper->GetNodeFromTree(
+        focused_wrapper->GetTreeID(), focus_id_);
+    if (!focused_node)
+      return;
+  }
+
   args.GetReturnValue().Set(
       gin::DataObjectBuilder(GetIsolate())
-          .Set("treeId", focused_tree_wrapper->GetTreeID().ToString())
+          .Set("treeId", focused_wrapper->GetTreeID().ToString())
           .Set("nodeId", focused_node->id())
           .Build());
 }
@@ -1955,6 +1963,17 @@ void AutomationInternalCustomBindings::GetAccessibilityFocus(
           .Build());
 }
 
+void AutomationInternalCustomBindings::SetDesktopID(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  if (args.Length() != 1 || !args[0]->IsString()) {
+    ThrowInvalidArgumentsException(this);
+    return;
+  }
+
+  desktop_tree_id_ = ui::AXTreeID::FromString(
+      *v8::String::Utf8Value(args.GetIsolate(), args[0]));
+}
+
 void AutomationInternalCustomBindings::GetHtmlAttributes(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = GetIsolate();
@@ -2522,32 +2541,43 @@ void AutomationInternalCustomBindings::MaybeSendFocusAndBlur(
   bool lost_old_focus = old_node == nullptr;
 
   // Determine whether there's a focus or blur event and take its event from.
+  // Also, save the raw event target (tree + node).
   ax::mojom::EventFrom event_from = ax::mojom::EventFrom::kNone;
-  bool event_bundle_has_focus_or_blur;
+  ui::AXNodeData::AXID raw_focus_target_id = ui::AXNodeData::kInvalidAXID;
+  bool event_bundle_has_focus_or_blur = false;
   for (const auto& event : event_bundle.events) {
-    if (event.event_type == ax::mojom::Event::kBlur ||
-        event.event_type == ax::mojom::Event::kFocus) {
+    bool is_blur = event.event_type == ax::mojom::Event::kBlur;
+    bool is_focus = event.event_type == ax::mojom::Event::kFocus;
+    if (is_blur || is_focus) {
       event_from = event.event_from;
       event_bundle_has_focus_or_blur = true;
-      break;
     }
+
+    if (is_focus)
+      raw_focus_target_id = event.id;
   }
 
   bool is_from_desktop = tree->IsDesktopTree();
   if (!event_bundle_has_focus_or_blur && !lost_old_focus && !is_from_desktop)
     return;
 
-  // Get the root-most tree.
-  AutomationAXTreeWrapper* root_tree = tree;
-  while ((tree = AutomationAXTreeWrapper::GetParentOfTreeId(
-              root_tree->GetTreeID())))
-    root_tree = tree;
-
+  AutomationAXTreeWrapper* desktop_tree =
+      GetAutomationAXTreeWrapperFromTreeID(desktop_tree_id_);
   ui::AXNode* new_node = nullptr;
   AutomationAXTreeWrapper* new_wrapper = nullptr;
-  if (!GetFocusInternal(root_tree, &new_wrapper, &new_node))
+  if (desktop_tree && !GetFocusInternal(desktop_tree, &new_wrapper, &new_node))
     return;
 
+  if (!desktop_tree) {
+    // Can occur if the extension does not have desktop permission,
+    // chrome.automation.getDesktop has yet to be called, or if this platform
+    // does not support Aura.
+    new_wrapper = tree;
+    new_node = tree->tree()->GetFromId(raw_focus_target_id);
+    if (!new_node)
+      return;
+  }
+
   if (new_wrapper == old_wrapper && new_node == old_node)
     return;
 

extensions/renderer/api/automation/automation_internal_custom_bindings.h

@@ -202,6 +202,9 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
   // accessibility focus.
   void GetAccessibilityFocus(const v8::FunctionCallbackInfo<v8::Value>& args);
 
+  // Args: string ax_tree_id.
+  void SetDesktopID(const v8::FunctionCallbackInfo<v8::Value>& args);
+
   // 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);
@@ -261,6 +264,9 @@ class AutomationInternalCustomBindings : public ObjectBackedNativeHandler {
   // as used in ui::AXTree.
   ui::AXTreeID accessibility_focused_tree_id_ = ui::AXTreeIDUnknown();
 
+  // Keeps track  of the single desktop tree, if it exists.
+  ui::AXTreeID desktop_tree_id_ = ui::AXTreeIDUnknown();
+
   DISALLOW_COPY_AND_ASSIGN(AutomationInternalCustomBindings);
 };
 

extensions/renderer/resources/automation/automation_custom_bindings.js

@@ -18,6 +18,8 @@ var RemoveTreeChangeObserver =
 var GetFocusNative = nativeAutomationInternal.GetFocus;
 var GetAccessibilityFocusNative =
     nativeAutomationInternal.GetAccessibilityFocus;
+var SetDesktopID =
+    nativeAutomationInternal.SetDesktopID;
 
 /**
  * A namespace to export utility functions to other files in automation.
@@ -102,10 +104,12 @@ automationUtil.tabIDToAutomationNode = {};
         if (bindingUtil.hasLastError()) {
           AutomationRootNode.destroy(treeId);
           desktopId = undefined;
+          SetDesktopID('');
           callback();
           return;
         }
         desktopId = treeId;
+        SetDesktopID(desktopId);
         desktopTree = AutomationRootNode.getOrCreate(desktopId);
         callback(desktopTree);
 
@@ -118,10 +122,7 @@ automationUtil.tabIDToAutomationNode = {};
   });
 
   apiFunctions.setHandleRequest('getFocus', function(callback) {
-    if (desktopId === undefined)
-      return;
-
-    var focusedNodeInfo = GetFocusNative(desktopId);
+    var focusedNodeInfo = GetFocusNative();
     if (!focusedNodeInfo) {
       callback(null);
       return;