Add onTapOutside to TextFormField (#108629)

packages/flutter/lib/src/material/text_form_field.dart

@@ -125,6 +125,7 @@ class TextFormField extends FormField<String> {
     int? maxLength,
     ValueChanged<String>? onChanged,
     GestureTapCallback? onTap,
+    TapRegionCallback? onTapOutside,
     VoidCallback? onEditingComplete,
     ValueChanged<String>? onFieldSubmitted,
     super.onSaved,
@@ -216,6 +217,7 @@ class TextFormField extends FormField<String> {
                maxLength: maxLength,
                onChanged: onChangedHandler,
                onTap: onTap,
+               onTapOutside: onTapOutside,
                onEditingComplete: onEditingComplete,
                onSubmitted: onFieldSubmitted,
                inputFormatters: inputFormatters,

packages/flutter/test/material/text_form_field_test.dart

@@ -728,6 +728,36 @@ void main() {
     expect(tapCount, 3);
   });
 
+  testWidgets('onTapOutside is called upon tap outside', (WidgetTester tester) async {
+    int tapOutsideCount = 0;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: Column(
+              children: <Widget>[
+                const Text('Outside'),
+                TextFormField(
+                  onTapOutside: (PointerEvent event) {
+                    tapOutsideCount += 1;
+                  },
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+    await tester.pump(); // Wait for autofocus to take effect.
+
+    expect(tapOutsideCount, 0);
+    await tester.tap(find.byType(TextFormField));
+    await tester.tap(find.text('Outside'));
+    await tester.tap(find.text('Outside'));
+    await tester.tap(find.text('Outside'));
+    expect(tapOutsideCount, 3);
+  });
+
   // Regression test for https://github.com/flutter/flutter/issues/54472.
   testWidgets('reset resets the text fields value to the initialValue', (WidgetTester tester) async {
     await tester.pumpWidget(