Support accessibility focus blocking for blocked semantics nodes

When a Flutter widget sets accessibilityFocusBlockType to blockNode,
mark the node as kIgnored so its ATK object is not created, making it
invisible to the AT-SPI tree and unreachable by the screen reader.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: JSUYA

flutter/shell/platform/common/accessibility_bridge.cc

@@ -377,6 +377,8 @@ void AccessibilityBridge::SetStateFromFlutterUpdate(ui::AXNodeData& node_data,
       (actions & kHasScrollingAction) == 0 && node.value.empty() &&
       node.label.empty() && node.hint.empty()) {
     node_data.AddState(ax::mojom::State::kIgnored);
+  } else if (flags->is_accessibility_focus_blocked) {
+    node_data.AddState(ax::mojom::State::kIgnored);
   } else {
     // kFlutterSemanticsFlagIsFocusable means a keyboard focusable, it is
     // different from semantics focusable.

flutter/shell/platform/common/flutter_platform_node_delegate.cc

@@ -62,12 +62,13 @@ const ui::AXNodeData& FlutterPlatformNodeDelegate::GetData() const {
 }
 
 gfx::NativeViewAccessible FlutterPlatformNodeDelegate::GetParent() {
-  if (!ax_node_->parent()) {
+  auto* unignored_parent = ax_node_->GetUnignoredParent();
+  if (!unignored_parent) {
     return nullptr;
   }
   auto bridge_ptr = bridge_.lock();
   BASE_DCHECK(bridge_ptr);
-  return bridge_ptr->GetNativeAccessibleFromId(ax_node_->parent()->id());
+  return bridge_ptr->GetNativeAccessibleFromId(unignored_parent->id());
 }
 
 gfx::NativeViewAccessible FlutterPlatformNodeDelegate::GetFocus() {

flutter/shell/platform/tizen/flutter_platform_node_delegate_tizen.cc

@@ -24,9 +24,29 @@ FlutterPlatformNodeDelegateTizen::~FlutterPlatformNodeDelegateTizen() {
 void FlutterPlatformNodeDelegateTizen::Init(std::weak_ptr<OwnerBridge> bridge,
                                             ui::AXNode* node) {
   FlutterPlatformNodeDelegate::Init(bridge, node);
-  platform_node_ = ui::AXPlatformNode::Create(this);
-  FT_LOG(Debug) << "Create platform node for AXNode "
-                << node->data().ToString();
+  if (!node->data().IsIgnored()) {
+    platform_node_ = ui::AXPlatformNode::Create(this);
+    FT_LOG(Debug) << "Create platform node for AXNode "
+                  << node->data().ToString();
+  }
+}
+
+void FlutterPlatformNodeDelegateTizen::NodeDataChanged(
+    const ui::AXNodeData& old_node_data,
+    const ui::AXNodeData& new_node_data) {
+  const bool was_ignored = old_node_data.IsIgnored();
+  const bool is_ignored = new_node_data.IsIgnored();
+
+  if (was_ignored && !is_ignored) {
+    if (!platform_node_) {
+      platform_node_ = ui::AXPlatformNode::Create(this);
+    }
+  } else if (!was_ignored && is_ignored) {
+    if (platform_node_) {
+      platform_node_->Destroy();
+      platform_node_ = nullptr;
+    }
+  }
 }
 
 void FlutterPlatformNodeDelegateTizen::NotifyAccessibilityEvent(

flutter/shell/platform/tizen/flutter_platform_node_delegate_tizen.h

@@ -39,6 +39,10 @@ class FlutterPlatformNodeDelegateTizen : public FlutterPlatformNodeDelegate {
   // |FlutterPlatformNodeDelegate|
   void Init(std::weak_ptr<OwnerBridge> bridge, ui::AXNode* node) override;
 
+  // |FlutterPlatformNodeDelegate|
+  void NodeDataChanged(const ui::AXNodeData& old_node_data,
+                       const ui::AXNodeData& new_node_data) override;
+
  private:
   ui::AXPlatformNode* platform_node_;
 };