Limit selection change to focused node on Windows (#38634)

* Limit selection change to focused node on Windows

* Focus fix

* Test document selection change

* Comment

* Formatting

* Update shell/platform/windows/accessibility_bridge_windows.cc

Co-authored-by: Loïc Sharma <[email protected]>

Co-authored-by: Loïc Sharma <[email protected]>

Author: yaakovschectman

shell/platform/common/accessibility_bridge.cc

@@ -527,11 +527,12 @@ void AccessibilityBridge::SetTooltipFromFlutterUpdate(
 void AccessibilityBridge::SetTreeData(const SemanticsNode& node,
                                       ui::AXTreeUpdate& tree_update) {
   FlutterSemanticsFlag flags = node.flags;
-  // Set selection if:
+  // Set selection of the focused node if:
   // 1. this text field has a valid selection
   // 2. this text field doesn't have a valid selection but had selection stored
   //    in the tree.
-  if (flags & FlutterSemanticsFlag::kFlutterSemanticsFlagIsTextField) {
+  if (flags & FlutterSemanticsFlag::kFlutterSemanticsFlagIsTextField &&
+      flags & FlutterSemanticsFlag::kFlutterSemanticsFlagIsFocused) {
     if (node.text_selection_base != -1) {
       tree_update.tree_data.sel_anchor_object_id = node.id;
       tree_update.tree_data.sel_anchor_offset = node.text_selection_base;

shell/platform/common/accessibility_bridge_unittests.cc

@@ -152,7 +152,9 @@ TEST(AccessibilityBridgeTest, canHandleSelectionChangeCorrectly) {
   std::shared_ptr<TestAccessibilityBridge> bridge =
       std::make_shared<TestAccessibilityBridge>();
   FlutterSemanticsNode root = CreateSemanticsNode(0, "root");
-  root.flags = FlutterSemanticsFlag::kFlutterSemanticsFlagIsTextField;
+  root.flags = static_cast<FlutterSemanticsFlag>(
+      FlutterSemanticsFlag::kFlutterSemanticsFlagIsTextField |
+      FlutterSemanticsFlag::kFlutterSemanticsFlagIsFocused);
   bridge->AddFlutterSemanticsNodeUpdate(&root);
   bridge->CommitUpdates();
 

shell/platform/windows/accessibility_bridge_windows.cc

@@ -41,10 +41,23 @@ void AccessibilityBridgeWindows::OnAccessibilityEvent(
       DispatchWinAccessibilityEvent(win_delegate,
                                     ax::mojom::Event::kChildrenChanged);
       break;
-    case ui::AXEventGenerator::Event::DOCUMENT_SELECTION_CHANGED:
+    case ui::AXEventGenerator::Event::DOCUMENT_SELECTION_CHANGED: {
+      // An event indicating a change in document selection should be fired
+      // only for the focused node whose selection has changed. If a valid
+      // caret and selection exist in the app tree, they must both be within
+      // the focus node.
+      ui::AXNode::AXID focus_id = GetAXTreeData().sel_focus_object_id;
+      auto focus_delegate =
+          GetFlutterPlatformNodeDelegateFromID(focus_id).lock();
+      if (!focus_delegate) {
+        win_delegate =
+            std::static_pointer_cast<FlutterPlatformNodeDelegateWindows>(
+                focus_delegate);
+      }
       DispatchWinAccessibilityEvent(
           win_delegate, ax::mojom::Event::kDocumentSelectionChanged);
       break;
+    }
     case ui::AXEventGenerator::Event::FOCUS_CHANGED:
       DispatchWinAccessibilityEvent(win_delegate, ax::mojom::Event::kFocus);
       SetFocus(win_delegate);

shell/platform/windows/accessibility_bridge_windows_unittests.cc

@@ -338,5 +338,11 @@ TEST(AccessibilityBridgeWindows, OnAccessibilityStateChanged) {
       ax::mojom::Event::kStateChanged);
 }
 
+TEST(AccessibilityBridgeWindows, OnDocumentSelectionChanged) {
+  ExpectWinEventFromAXEvent(
+      1, ui::AXEventGenerator::Event::DOCUMENT_SELECTION_CHANGED,
+      ax::mojom::Event::kDocumentSelectionChanged);
+}
+
 }  // namespace testing
 }  // namespace flutter