macOS: Update platform node when AXNodeData role changes (#54364)

Fixes flutter/flutter#151428

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Author: knopp

shell/platform/common/accessibility_bridge.cc

@@ -163,6 +163,17 @@ void AccessibilityBridge::OnRoleChanged(ui::AXTree* tree,
                                         ax::mojom::Role old_role,
                                         ax::mojom::Role new_role) {}
 
+void AccessibilityBridge::OnNodeDataChanged(
+    ui::AXTree* tree,
+    const ui::AXNodeData& old_node_data,
+    const ui::AXNodeData& new_node_data) {
+  auto platform_view =
+      GetFlutterPlatformNodeDelegateFromID(new_node_data.id).lock();
+  if (platform_view) {
+    platform_view->NodeDataChanged(old_node_data, new_node_data);
+  }
+}
+
 void AccessibilityBridge::OnNodeCreated(ui::AXTree* tree, ui::AXNode* node) {
   BASE_DCHECK(node);
   id_wrapper_map_[node->id()] = CreateFlutterPlatformNodeDelegate();

shell/platform/common/accessibility_bridge.h

@@ -260,6 +260,11 @@ class AccessibilityBridge
                      ax::mojom::Role old_role,
                      ax::mojom::Role new_role) override;
 
+  // |AXTreeObserver|
+  void OnNodeDataChanged(ui::AXTree* tree,
+                         const ui::AXNodeData& old_node_data,
+                         const ui::AXNodeData& new_node_data) override;
+
   // |AXTreeObserver|
   void OnAtomicUpdateFinished(
       ui::AXTree* tree,

shell/platform/common/flutter_platform_node_delegate.h

@@ -139,6 +139,12 @@ class FlutterPlatformNodeDelegate : public ui::AXPlatformNodeDelegateBase {
   ///             Subclasses must call super.
   virtual void Init(std::weak_ptr<OwnerBridge> bridge, ui::AXNode* node);
 
+  //------------------------------------------------------------------------------
+  // @brief       Called when node was updated. Subclasses can override this
+  //              to update platform nodes.
+  virtual void NodeDataChanged(const ui::AXNodeData& old_node_data,
+                               const ui::AXNodeData& new_node_data) {}
+
   //------------------------------------------------------------------------------
   /// @brief      Gets the underlying ax node for this platform node delegate.
   ui::AXNode* GetAXNode() const;

shell/platform/darwin/macos/framework/Source/AccessibilityBridgeMac.mm

@@ -165,11 +165,11 @@
         // If it is a text field, the value change notifications are handled by
         // the FlutterTextField directly. Only need to make sure it is the
         // first responder.
-        FlutterTextField* native_text_field =
-            (FlutterTextField*)mac_platform_node_delegate->GetNativeViewAccessible();
+        id native_text_field = mac_platform_node_delegate->GetNativeViewAccessible();
+        FML_DCHECK([native_text_field isKindOfClass:FlutterTextField.class]);
         id focused = mac_platform_node_delegate->GetFocus();
         if (!focused || native_text_field == focused) {
-          [native_text_field startEditing];
+          [(FlutterTextField*)native_text_field startEditing];
         }
         break;
       }

shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMac.h

@@ -27,6 +27,9 @@ class FlutterPlatformNodeDelegateMac : public FlutterPlatformNodeDelegate {
 
   void Init(std::weak_ptr<OwnerBridge> bridge, ui::AXNode* node) override;
 
+  void NodeDataChanged(const ui::AXNodeData& old_node_data,
+                       const ui::AXNodeData& new_node_data) override;
+
   //---------------------------------------------------------------------------
   /// @brief      Gets the live region text of this node in UTF-8 format. This
   ///             is useful to determine the changes in between semantics

shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMac.mm

@@ -35,6 +35,17 @@
   NSCAssert(ax_platform_node_, @"Failed to create platform node.");
 }
 
+void FlutterPlatformNodeDelegateMac::NodeDataChanged(const ui::AXNodeData& old_node_data,
+                                                     const ui::AXNodeData& new_node_data) {
+  if (old_node_data.IsTextField() && !new_node_data.IsTextField()) {
+    ax_platform_node_->Destroy();
+    ax_platform_node_ = ui::AXPlatformNode::Create(this);
+  } else if (!old_node_data.IsTextField() && new_node_data.IsTextField()) {
+    ax_platform_node_->Destroy();
+    ax_platform_node_ = new FlutterTextPlatformNode(this, view_controller_);
+  }
+}
+
 FlutterPlatformNodeDelegateMac::~FlutterPlatformNodeDelegateMac() {
   // Destroy() also calls delete on itself.
   ax_platform_node_->Destroy();

shell/platform/darwin/macos/framework/Source/FlutterPlatformNodeDelegateMacTest.mm

@@ -296,4 +296,81 @@
   EXPECT_EQ([native_text_field.stringValue isEqualToString:@"textfield"], YES);
 }
 
+TEST(FlutterPlatformNodeDelegateMac, ChangingFlagsUpdatesNativeViewAccessible) {
+  FlutterViewController* viewController = CreateTestViewController();
+  FlutterEngine* engine = viewController.engine;
+  [viewController loadView];
+
+  // Creates a NSWindow so that the native text field can become first responder.
+  NSWindow* window = [[NSWindow alloc] initWithContentRect:NSMakeRect(0, 0, 800, 600)
+                                                 styleMask:NSBorderlessWindowMask
+                                                   backing:NSBackingStoreBuffered
+                                                     defer:NO];
+  window.contentView = viewController.view;
+  engine.semanticsEnabled = YES;
+
+  auto bridge = viewController.accessibilityBridge.lock();
+  // Initialize ax node data.
+  FlutterSemanticsNode2 root;
+  root.id = 0;
+  root.flags = static_cast<FlutterSemanticsFlag>(0);
+  root.actions = static_cast<FlutterSemanticsAction>(0);
+  root.label = "root";
+  root.hint = "";
+  root.value = "";
+  root.increased_value = "";
+  root.decreased_value = "";
+  root.tooltip = "";
+  root.child_count = 1;
+  int32_t children[] = {1};
+  root.children_in_traversal_order = children;
+  root.custom_accessibility_actions_count = 0;
+  root.rect = {0, 0, 100, 100};  // LTRB
+  root.transform = {1, 0, 0, 0, 1, 0, 0, 0, 1};
+  bridge->AddFlutterSemanticsNodeUpdate(root);
+
+  double rectSize = 50;
+  double transformFactor = 0.5;
+
+  FlutterSemanticsNode2 child1;
+  child1.id = 1;
+  child1.flags = static_cast<FlutterSemanticsFlag>(0);
+  child1.actions = static_cast<FlutterSemanticsAction>(0);
+  child1.label = "";
+  child1.hint = "";
+  child1.value = "textfield";
+  child1.increased_value = "";
+  child1.decreased_value = "";
+  child1.tooltip = "";
+  child1.text_selection_base = -1;
+  child1.text_selection_extent = -1;
+  child1.child_count = 0;
+  child1.custom_accessibility_actions_count = 0;
+  child1.rect = {0, 0, rectSize, rectSize};  // LTRB
+  child1.transform = {transformFactor, 0, 0, 0, transformFactor, 0, 0, 0, 1};
+  bridge->AddFlutterSemanticsNodeUpdate(child1);
+
+  bridge->CommitUpdates();
+
+  auto child_platform_node_delegate = bridge->GetFlutterPlatformNodeDelegateFromID(1).lock();
+  // Verify the accessibility attribute matches.
+  id native_accessibility = child_platform_node_delegate->GetNativeViewAccessible();
+  EXPECT_TRUE([[native_accessibility className] isEqualToString:@"AXPlatformNodeCocoa"]);
+
+  // Converting child to text field should produce `FlutterTextField` native view accessible.
+  child1.flags = FlutterSemanticsFlag::kFlutterSemanticsFlagIsTextField;
+  bridge->AddFlutterSemanticsNodeUpdate(child1);
+  bridge->CommitUpdates();
+
+  native_accessibility = child_platform_node_delegate->GetNativeViewAccessible();
+  EXPECT_TRUE([native_accessibility isKindOfClass:[FlutterTextField class]]);
+
+  child1.flags = static_cast<FlutterSemanticsFlag>(0);
+  bridge->AddFlutterSemanticsNodeUpdate(child1);
+  bridge->CommitUpdates();
+
+  native_accessibility = child_platform_node_delegate->GetNativeViewAccessible();
+  EXPECT_TRUE([[native_accessibility className] isEqualToString:@"AXPlatformNodeCocoa"]);
+}
+
 }  // namespace flutter::testing

shell/platform/darwin/macos/framework/Source/FlutterTextInputSemanticsObject.mm

@@ -190,6 +190,9 @@ - (void)dealloc {
   FlutterPlatformNodeDelegate* delegate = static_cast<FlutterPlatformNodeDelegate*>(GetDelegate());
   bool offscreen;
   auto bridge_ptr = delegate->GetOwnerBridge().lock();
+  if (!bridge_ptr) {
+    return NSZeroRect;
+  }
   gfx::RectF bounds = bridge_ptr->RelativeToGlobalBounds(delegate->GetAXNode(), offscreen, true);
 
   // Converts to NSRect to use NSView rect conversion.

shell/platform/darwin/macos/framework/Source/FlutterViewController.mm

@@ -519,7 +519,8 @@ - (BOOL)attached {
 }
 
 - (void)updateSemantics:(const FlutterSemanticsUpdate2*)update {
-  NSAssert(_engine.semanticsEnabled, @"Semantics must be enabled.");
+  // Semantics will be disabled when unfocusing application but the updateSemantics:
+  // callback is received in next run loop turn.
   if (!_engine.semanticsEnabled) {
     return;
   }