[web] Set the correct href on semantic links

Author: mdebbar

lib/web_ui/lib/src/engine/semantics/link.dart

@@ -18,9 +18,8 @@ class Link extends PrimaryRoleManager {
   @override
   DomElement createElement() {
     final DomElement element = domDocument.createElement('a');
-    // TODO(chunhtai): Fill in the real link once the framework sends entire uri.
-    // https://github.com/flutter/flutter/issues/102535.
-    element.setAttribute('href', '#');
+    // TODO: The <a> element has `aria-label={value}`. We should stop that!
+    element.setAttribute('href', semanticsObject.hasValue ? semanticsObject.value! : '#');
     element.style.display = 'block';
     return element;
   }

lib/web_ui/lib/src/engine/semantics/semantics.dart

@@ -478,6 +478,10 @@ abstract class PrimaryRoleManager {
     element.style.position = 'absolute';
     element.setAttribute('id', 'flt-semantic-node-${semanticsObject.id}');
 
+    if (semanticsObject.hasIdentifier) {
+      element.setAttribute('semantic-identifier', semanticsObject.identifier!);
+    }
+
     // The root node has some properties that other nodes do not.
     if (semanticsObject.id == 0 && !configuration.debugShowSemanticsNodes) {
       // Make all semantics transparent. Use `filter` instead of `opacity`
@@ -1085,6 +1089,21 @@ class SemanticsObject {
     _dirtyFields |= _platformViewIdIndex;
   }
 
+  /// See [ui.SemanticsUpdateBuilder.updateNode].
+  String? get identifier => _identifier;
+  String? _identifier;
+
+  bool get hasIdentifier => _identifier != null && _identifier!.isNotEmpty;
+
+  static const int _identifierIndex = 1 << 24;
+
+  /// Whether the [identifier] field has been updated but has not been
+  /// applied to the DOM yet.
+  bool get isIdentifierDirty => _isDirty(_identifierIndex);
+  void _markIdentifierDirty() {
+    _dirtyFields |= _identifierIndex;
+  }
+
   /// A unique permanent identifier of the semantics node in the tree.
   final int id;
 
@@ -1241,6 +1260,11 @@ class SemanticsObject {
       _markFlagsDirty();
     }
 
+    if (_identifier != update.identifier) {
+      _identifier = update.identifier;
+      _markIdentifierDirty();
+    }
+
     if (_value != update.value) {
       _value = update.value;
       _markValueDirty();