Android context menu theming and visual update (#131816)

Fixes https://github.com/flutter/flutter/issues/89939 and updates the look of the Android context menu to match API 34.

## The problem
Before this PR, setting `surface` in the color scheme caused the background color of the Android context menu to change, but it wasn't possible to change the text color.

```dart
MaterialApp(
  theme: ThemeData(
    // Using a dark theme made the context menu text color be white.
    colorScheme: ThemeData.dark().colorScheme.copyWith(
      // Setting the surface here worked.
      surface: Colors.white,
      // But there was no way to set the text color. This didn't work.
      onSurface: Colors.black,
    ),
  ),
),
```

| Expected (after PR) | Actual (before PR) |
| --- | --- |
| <img width="239" alt="Screenshot 2023-08-07 at 11 45 37 AM" src="https://github.com/flutter/flutter/assets/389558/a9fb75e5-b6c3-4f8e-8c59-2021780c44a7"> | <img width="250" alt="Screenshot 2023-08-07 at 11 51 10 AM" src="https://github.com/flutter/flutter/assets/389558/a5abd2d2-49bb-47a0-836f-864d56af2f58"> |

## Other examples

<table>
<tr>
<th>Scenario</th>
<th>Result</th>
</tr>
<tr>
<td>

```dart
MaterialApp(
  theme: ThemeData(
    colorScheme: ThemeData.light(),
  ),
  ...
),
```

</td>
<td>
<img width="244" alt="Screenshot 2023-08-07 at 11 42 05 AM" src="https://github.com/flutter/flutter/assets/389558/74c6870b-5ff7-4b1a-9e0c-b2bb4809ef1e">
</td>
</tr>
<tr>
<td>

```dart
MaterialApp(
  theme: ThemeData(
    colorScheme: ThemeData.dark(),
  ),
  ...
),
```

</td>
<td>
<img width="239" alt="Screenshot 2023-08-07 at 11 42 23 AM" src="https://github.com/flutter/flutter/assets/389558/91fe32f8-bd62-4d9b-96e8-ae5a9a769745">
</td>
</tr>
<tr>
<td>

```dart
MaterialApp(
  theme: ThemeData(
    colorScheme: ThemeData.light().colorScheme.copyWith(
      surface: Colors.blue,
      onSurface: Colors.red,
    ),
  ),
  ...
),
```

</td>
<td>
<img width="240" alt="Screenshot 2023-08-07 at 11 43 06 AM" src="https://github.com/flutter/flutter/assets/389558/e5752f8b-3738-4391-9055-15c38bd4af21">
</td>
</tr>
<tr>
<td>

```dart
MaterialApp(
  theme: ThemeData(
    colorScheme: ThemeData.light().colorScheme.copyWith(
      surface: Colors.blue,
      onSurface: Colors.red,
    ),
  ),
  ...
),
```

</td>
<td>
<img width="244" alt="Screenshot 2023-08-07 at 11 42 47 AM" src="https://github.com/flutter/flutter/assets/389558/68cc68f0-b338-4d94-8810-d8e46fb1e48e">
</td>
</tr>
</table>

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

@@ -8,11 +8,13 @@ import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart' show listEquals;
 import 'package:flutter/rendering.dart';
 
+import 'color_scheme.dart';
 import 'debug.dart';
 import 'icon_button.dart';
 import 'icons.dart';
 import 'material.dart';
 import 'material_localizations.dart';
+import 'theme.dart';
 
 const double _kToolbarHeight = 44.0;
 const double _kToolbarContentDistance = 8.0;
@@ -650,13 +652,34 @@ class _TextSelectionToolbarContainer extends StatelessWidget {
 
   final Widget child;
 
+  // These colors were taken from a screenshot of a Pixel 6 emulator running
+  // Android API level 34.
+  static const Color _defaultColorLight = Color(0xffffffff);
+  static const Color _defaultColorDark = Color(0xff424242);
+
+  static Color _getColor(ColorScheme colorScheme) {
+    final bool isDefaultSurface = switch (colorScheme.brightness) {
+      Brightness.light => identical(ThemeData().colorScheme.surface, colorScheme.surface),
+      Brightness.dark => identical(ThemeData.dark().colorScheme.surface, colorScheme.surface),
+    };
+    if (!isDefaultSurface) {
+      return colorScheme.surface;
+    }
+    return switch (colorScheme.brightness) {
+      Brightness.light => _defaultColorLight,
+      Brightness.dark => _defaultColorDark,
+    };
+  }
+
   @override
   Widget build(BuildContext context) {
+    final ThemeData theme = Theme.of(context);
     return Material(
       // This value was eyeballed to match the native text selection menu on
-      // a Pixel 2 running Android 10.
+      // a Pixel 6 emulator running Android API level 34.
-      borderRadius: const BorderRadius.all(Radius.circular(7.0)),
+      borderRadius: const BorderRadius.all(Radius.circular(_kToolbarHeight / 2)),
       clipBehavior: Clip.antiAlias,
+      color: _getColor(theme.colorScheme),
       elevation: 1.0,
       type: MaterialType.card,
       child: child,

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

@@ -4,7 +4,7 @@
 
 import 'package:flutter/widgets.dart';
 
-import 'colors.dart';
+import 'color_scheme.dart';
 import 'constants.dart';
 import 'text_button.dart';
 import 'theme.dart';
@@ -130,20 +130,40 @@ class TextSelectionToolbarTextButton extends StatelessWidget {
     );
   }
 
+  // These colors were taken from a screenshot of a Pixel 6 emulator running
+  // Android API level 34.
+  static const Color _defaultForegroundColorLight = Color(0xff000000);
+  static const Color _defaultForegroundColorDark = Color(0xffffffff);
+
+  static Color _getForegroundColor(ColorScheme colorScheme) {
+    final bool isDefaultOnSurface = switch (colorScheme.brightness) {
+      Brightness.light => identical(ThemeData().colorScheme.onSurface, colorScheme.onSurface),
+      Brightness.dark => identical(ThemeData.dark().colorScheme.onSurface, colorScheme.onSurface),
+    };
+    if (!isDefaultOnSurface) {
+      return colorScheme.onSurface;
+    }
+    return switch (colorScheme.brightness) {
+      Brightness.light => _defaultForegroundColorLight,
+      Brightness.dark => _defaultForegroundColorDark,
+    };
+  }
+
   @override
   Widget build(BuildContext context) {
-    // TODO(hansmuller): Should be colorScheme.onSurface
+    final ColorScheme colorScheme = Theme.of(context).colorScheme;
-    final ThemeData theme = Theme.of(context);
-    final bool isDark = theme.colorScheme.brightness == Brightness.dark;
-    final Color foregroundColor = isDark ? Colors.white : Colors.black87;
-
     return TextButton(
       style: TextButton.styleFrom(
-        foregroundColor: foregroundColor,
+        foregroundColor: _getForegroundColor(colorScheme),
         shape: const RoundedRectangleBorder(),
         minimumSize: const Size(kMinInteractiveDimension, kMinInteractiveDimension),
         padding: padding,
         alignment: alignment,
+        textStyle: const TextStyle(
+          // This value was eyeballed from a screenshot of a Pixel 6 emulator
+          // running Android API level 34.
+          fontWeight: FontWeight.w400,
+        ),
       ),
       onPressed: onPressed,
       child: child,

packages/flutter/test/material/text_selection_toolbar_test.dart

@@ -204,4 +204,93 @@ void main() {
     expect(find.text('Paste'), findsNothing);
     expect(find.text('Select all'), findsNothing);
   }, skip: kIsWeb); // [intended] We don't show the toolbar on the web.
+
+  for (final ColorScheme colorScheme in <ColorScheme>[ThemeData.light().colorScheme, ThemeData.dark().colorScheme]) {
+    testWidgetsWithLeakTracking('default background color', (WidgetTester tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: ThemeData(
+            colorScheme: colorScheme,
+          ),
+          home: Scaffold(
+            body: Center(
+              child: TextSelectionToolbar(
+                anchorAbove: Offset.zero,
+                anchorBelow: Offset.zero,
+                children: <Widget>[
+                  TextSelectionToolbarTextButton(
+                    padding: TextSelectionToolbarTextButton.getPadding(0, 1),
+                    onPressed: () {},
+                    child: const Text('Custom button'),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        ),
+      );
+
+      Finder findToolbarContainer() {
+        return find.descendant(
+          of: find.byWidgetPredicate((Widget w) => '${w.runtimeType}' == '_TextSelectionToolbarContainer'),
+          matching: find.byType(Material),
+        );
+      }
+      expect(findToolbarContainer(), findsAtLeastNWidgets(1));
+
+      final Material toolbarContainer = tester.widget(findToolbarContainer().first);
+      expect(
+        toolbarContainer.color,
+        // The default colors are hardcoded and don't take the default value of
+        // the theme's surface color.
+        switch (colorScheme.brightness) {
+          Brightness.light => const Color(0xffffffff),
+          Brightness.dark => const Color(0xff424242),
+        },
+      );
+    });
+
+    testWidgetsWithLeakTracking('custom background color', (WidgetTester tester) async {
+      const Color customBackgroundColor = Colors.red;
+
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: ThemeData(
+            colorScheme: colorScheme.copyWith(
+              surface: customBackgroundColor,
+            ),
+          ),
+          home: Scaffold(
+            body: Center(
+              child: TextSelectionToolbar(
+                anchorAbove: Offset.zero,
+                anchorBelow: Offset.zero,
+                children: <Widget>[
+                  TextSelectionToolbarTextButton(
+                    padding: TextSelectionToolbarTextButton.getPadding(0, 1),
+                    onPressed: () {},
+                    child: const Text('Custom button'),
+                  ),
+                ],
+              ),
+            ),
+          ),
+        ),
+      );
+
+      Finder findToolbarContainer() {
+        return find.descendant(
+          of: find.byWidgetPredicate((Widget w) => '${w.runtimeType}' == '_TextSelectionToolbarContainer'),
+          matching: find.byType(Material),
+        );
+      }
+      expect(findToolbarContainer(), findsAtLeastNWidgets(1));
+
+      final Material toolbarContainer = tester.widget(findToolbarContainer().first);
+      expect(
+        toolbarContainer.color,
+        customBackgroundColor,
+      );
+    });
+  }
 }

packages/flutter/test/material/text_selection_toolbar_text_button_test.dart

@@ -62,4 +62,67 @@ void main() {
     expect(onlySize.width, greaterThan(firstSize.width));
     expect(onlySize.width, greaterThan(lastSize.width));
   });
+
+  for (final ColorScheme colorScheme in <ColorScheme>[ThemeData.light().colorScheme, ThemeData.dark().colorScheme]) {
+    testWidgetsWithLeakTracking('foreground color by default', (WidgetTester tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: ThemeData(
+            colorScheme: colorScheme,
+          ),
+          home: Scaffold(
+            body: Center(
+              child: TextSelectionToolbarTextButton(
+                padding: TextSelectionToolbarTextButton.getPadding(0, 1),
+                child: const Text('button'),
+              ),
+            ),
+          ),
+        ),
+      );
+
+      expect(find.byType(TextButton), findsOneWidget);
+
+      final TextButton textButton = tester.widget(find.byType(TextButton));
+      // The foreground color is hardcoded to black or white by default, not the
+      // default value from ColorScheme.onSurface.
+      expect(
+        textButton.style!.foregroundColor!.resolve(<MaterialState>{}),
+        switch (colorScheme.brightness) {
+          Brightness.light => const Color(0xff000000),
+          Brightness.dark => const Color(0xffffffff),
+        },
+      );
+    });
+
+    testWidgetsWithLeakTracking('custom foreground color', (WidgetTester tester) async {
+      const Color customForegroundColor = Colors.red;
+
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: ThemeData(
+            colorScheme: colorScheme.copyWith(
+              onSurface: customForegroundColor,
+            ),
+          ),
+          home: Scaffold(
+            body: Center(
+              child: TextSelectionToolbarTextButton(
+                padding: TextSelectionToolbarTextButton.getPadding(0, 1),
+                child: const Text('button'),
+              ),
+            ),
+          ),
+        ),
+      );
+
+      expect(find.byType(TextButton), findsOneWidget);
+
+      final TextButton textButton = tester.widget(find.byType(TextButton));
+      expect(
+        textButton.style!.foregroundColor!.resolve(<MaterialState>{}),
+        customForegroundColor,
+      );
+    });
+  }
 }