Fix `DatePicker` Dialog content not visible on lower text scale (#139236)

fixes [`DatePicker` dialog contents are hidden when using smaller text size](https://github.com/flutter/flutter/issues/139120)

### Description
- Fixed `DatePicker` dialog contents are hidden when using smaller text size.
- Add golden tests

### Golden Test (Before)

| `TextScale - 0.88` | `TextScale - 1.0` | `TextScale - 2.0` | 
| --------------- |  --------------- |  --------------- | 
|   <img src="https://github.com/flutter/flutter/assets/48603081/9f301c5d-3acd-4a9f-8fb7-aa7b2e9553a2"> |  <img src="https://github.com/flutter/flutter/assets/48603081/0496cf1a-5086-4cb1-ad3f-256f34346920"> | <img src="https://github.com/flutter/flutter/assets/48603081/2d1e1892-435a-4938-a7fc-2ffa4684828b"> | 

### Golden Test (After)

| `TextScale - 0.88` | `TextScale - 1.0` | `TextScale - 2.0` | 
| --------------- |  --------------- |  --------------- | 
|   <img src="https://github.com/flutter/flutter/assets/48603081/8fb922b7-0f2c-4f08-a091-b359a01e3600"> |  <img src="https://github.com/flutter/flutter/assets/48603081/59933cbf-49ef-46fb-98b5-217db2cc0ee7"> | <img src="https://github.com/flutter/flutter/assets/48603081/fd2501cb-511c-4b57-a4eb-f583af60aed7"> |

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

@@ -687,7 +687,7 @@ class _DatePickerDialogState extends State<DatePickerDialog> with RestorationMix
             final Size portraitDialogSize = useMaterial3 ? _inputPortraitDialogSizeM3 : _inputPortraitDialogSizeM2;
             // Make sure the portrait dialog can fit the contents comfortably when
             // resized from the landscape dialog.
-            final bool isFullyPortrait = constraints.maxHeight >= portraitDialogSize.height;
+            final bool isFullyPortrait = constraints.maxHeight >= math.min(dialogSize.height, portraitDialogSize.height);
 
             switch (orientation) {
               case Orientation.portrait:
@@ -2874,6 +2874,8 @@ class _InputDateRangePickerDialog extends StatelessWidget {
       ),
     );
 
+    final double textScaleFactor = MediaQuery.textScalerOf(context).clamp(maxScaleFactor: _kMaxTextScaleFactor).textScaleFactor;
+    final Size dialogSize = (useMaterial3 ? _inputPortraitDialogSizeM3 : _inputPortraitDialogSizeM2) * textScaleFactor;
     switch (orientation) {
       case Orientation.portrait:
         return LayoutBuilder(
@@ -2881,7 +2883,7 @@ class _InputDateRangePickerDialog extends StatelessWidget {
             final Size portraitDialogSize = useMaterial3 ? _inputPortraitDialogSizeM3 : _inputPortraitDialogSizeM2;
             // Make sure the portrait dialog can fit the contents comfortably when
             // resized from the landscape dialog.
-            final bool isFullyPortrait = constraints.maxHeight >= portraitDialogSize.height;
+            final bool isFullyPortrait = constraints.maxHeight >= math.min(dialogSize.height, portraitDialogSize.height);
 
             return Column(
               mainAxisSize: MainAxisSize.min,

packages/flutter/test/material/date_picker_test.dart

@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// This file is run as part of a reduced test set in CI on Mac and Windows
+// machines.
+@Tags(<String>['reduced-test-set'])
+library;
+
 import 'dart:ui';
 
 import 'package:flutter/foundation.dart';
@@ -69,20 +74,24 @@ void main() {
     TextDirection textDirection = TextDirection.ltr,
     bool useMaterial3 = false,
     ThemeData? theme,
+    TextScaler textScaler = TextScaler.noScaling,
   }) async {
     late BuildContext buttonContext;
     await tester.pumpWidget(MaterialApp(
       theme: theme ?? ThemeData(useMaterial3: useMaterial3),
-      home: Material(
-        child: Builder(
-          builder: (BuildContext context) {
-            return ElevatedButton(
-              onPressed: () {
-                buttonContext = context;
-              },
-              child: const Text('Go'),
-            );
-          },
+      home: MediaQuery(
+        data: MediaQueryData(textScaler: textScaler),
+        child: Material(
+          child: Builder(
+            builder: (BuildContext context) {
+              return ElevatedButton(
+                onPressed: () {
+                  buttonContext = context;
+                },
+                child: const Text('Go'),
+              );
+            },
+          ),
         ),
       ),
     ));
@@ -1472,7 +1481,7 @@ void main() {
     });
 
     // This is a regression test for https://github.com/flutter/flutter/issues/131989.
-    testWidgetsWithLeakTracking('Dialog contents do not overflow when resized from landscape to portrait',
+    testWidgetsWithLeakTracking('Dialog contents do not overflow when resized during orientation change',
       (WidgetTester tester) async {
         addTearDown(tester.view.reset);
         // Initial window size is wide for landscape mode.
@@ -1486,6 +1495,36 @@ void main() {
           expect(tester.takeException(), null);
         });
     });
+
+    // This is a regression test for https://github.com/flutter/flutter/issues/139120.
+    testWidgetsWithLeakTracking('Dialog contents are visible - textScaler 0.88, 1.0, 2.0',
+      (WidgetTester tester) async {
+        addTearDown(tester.view.reset);
+        tester.view.physicalSize = const Size(400, 800);
+        tester.view.devicePixelRatio = 1.0;
+        final List<double> scales = <double>[0.88, 1.0, 2.0];
+
+        for (final double scale in scales) {
+          await tester.pumpWidget(
+            MaterialApp(
+              home: MediaQuery(
+                data: MediaQueryData(textScaler: TextScaler.linear(scale)),
+                child: Material(
+                  child: DatePickerDialog(
+                    firstDate: DateTime(2001),
+                    lastDate: DateTime(2031, DateTime.december, 31),
+                    initialDate: DateTime(2016, DateTime.january, 15),
+                    initialEntryMode: DatePickerEntryMode.input,
+                  ),
+                ),
+              ),
+            ),
+          );
+          await tester.pumpAndSettle();
+
+          await expectLater(find.byType(Dialog), matchesGoldenFile('date_picker.dialog.contents.visible.$scale.png'));
+        }
+    });
   });
 
   group('Semantics', () {