Fix handling of iconSize and iconColor defaults for ButtonStyleButton subclasses. (#143501)

## Description

Adds defaults that use tokens to define default `iconSize` and `iconColor` values. Previously, the Material 3 token values for button icon sizes and colors were not being used as defaults when the `ButtonStyleButton.defaultStyleOf` function returned the default values.

Adds tests to make sure appropriate `ButtonStyle` fields are populated when defaultStyle is called on buttons.

Updated documentation for `defaultStyleOf` to indicated that not _all_ fields need to be non-null, since some fields make sense to be null (e.g. `fixedSize`) because they would otherwise override the behavior of other fields in the same `ButtonStyle`.

## Tests
 - Added tests to make sure that the appropriate fields are non-null in the default button styles for each type of button.

dev/tools/gen_defaults/generated/used_tokens.csv

@@ -145,6 +145,13 @@ md.comp.elevated-button.label-text.text-style,
 md.comp.elevated-button.pressed.container.elevation,
 md.comp.elevated-button.pressed.state-layer.color,
 md.comp.elevated-button.pressed.state-layer.opacity,
+md.comp.elevated-button.with-icon.disabled.icon.color,
+md.comp.elevated-button.with-icon.disabled.icon.opacity,
+md.comp.elevated-button.with-icon.focus.icon.color,
+md.comp.elevated-button.with-icon.hover.icon.color,
+md.comp.elevated-button.with-icon.icon.color,
+md.comp.elevated-button.with-icon.icon.size,
+md.comp.elevated-button.with-icon.pressed.icon.color,
 md.comp.elevated-card.container.color,
 md.comp.elevated-card.container.elevation,
 md.comp.elevated-card.container.shadow-color,
@@ -198,6 +205,13 @@ md.comp.filled-button.label-text.text-style,
 md.comp.filled-button.pressed.container.elevation,
 md.comp.filled-button.pressed.state-layer.color,
 md.comp.filled-button.pressed.state-layer.opacity,
+md.comp.filled-button.with-icon.disabled.icon.color,
+md.comp.filled-button.with-icon.disabled.icon.opacity,
+md.comp.filled-button.with-icon.focus.icon.color,
+md.comp.filled-button.with-icon.hover.icon.color,
+md.comp.filled-button.with-icon.icon.color,
+md.comp.filled-button.with-icon.icon.size,
+md.comp.filled-button.with-icon.pressed.icon.color,
 md.comp.filled-card.container.color,
 md.comp.filled-card.container.elevation,
 md.comp.filled-card.container.shadow-color,
@@ -296,6 +310,13 @@ md.comp.filled-tonal-button.label-text.text-style,
 md.comp.filled-tonal-button.pressed.container.elevation,
 md.comp.filled-tonal-button.pressed.state-layer.color,
 md.comp.filled-tonal-button.pressed.state-layer.opacity,
+md.comp.filled-tonal-button.with-icon.disabled.icon.color,
+md.comp.filled-tonal-button.with-icon.disabled.icon.opacity,
+md.comp.filled-tonal-button.with-icon.focus.icon.color,
+md.comp.filled-tonal-button.with-icon.hover.icon.color,
+md.comp.filled-tonal-button.with-icon.icon.color,
+md.comp.filled-tonal-button.with-icon.icon.size,
+md.comp.filled-tonal-button.with-icon.pressed.icon.color,
 md.comp.filled-tonal-icon-button.container.color,
 md.comp.filled-tonal-icon-button.container.height,
 md.comp.filled-tonal-icon-button.container.shape,
@@ -405,6 +426,7 @@ md.comp.list.list-item.hover.state-layer.opacity,
 md.comp.list.list-item.label-text.color,
 md.comp.list.list-item.label-text.text-style,
 md.comp.list.list-item.leading-icon.color,
+md.comp.list.list-item.leading-icon.size,
 md.comp.list.list-item.pressed.label-text.color,
 md.comp.list.list-item.pressed.leading-icon.icon.color,
 md.comp.list.list-item.pressed.state-layer.color,
@@ -470,6 +492,13 @@ md.comp.outlined-button.outline.color,
 md.comp.outlined-button.outline.width,
 md.comp.outlined-button.pressed.state-layer.color,
 md.comp.outlined-button.pressed.state-layer.opacity,
+md.comp.outlined-button.with-icon.disabled.icon.color,
+md.comp.outlined-button.with-icon.disabled.icon.opacity,
+md.comp.outlined-button.with-icon.focus.icon.color,
+md.comp.outlined-button.with-icon.hover.icon.color,
+md.comp.outlined-button.with-icon.icon.color,
+md.comp.outlined-button.with-icon.icon.size,
+md.comp.outlined-button.with-icon.pressed.icon.color,
 md.comp.outlined-card.container.color,
 md.comp.outlined-card.container.elevation,
 md.comp.outlined-card.container.shadow-color,
@@ -703,6 +732,13 @@ md.comp.text-button.label-text.color,
 md.comp.text-button.label-text.text-style,
 md.comp.text-button.pressed.state-layer.color,
 md.comp.text-button.pressed.state-layer.opacity,
+md.comp.text-button.with-icon.disabled.icon.color,
+md.comp.text-button.with-icon.disabled.icon.opacity,
+md.comp.text-button.with-icon.focus.icon.color,
+md.comp.text-button.with-icon.hover.icon.color,
+md.comp.text-button.with-icon.icon.color,
+md.comp.text-button.with-icon.icon.size,
+md.comp.text-button.with-icon.pressed.icon.color,
 md.comp.time-picker.clock-dial.color,
 md.comp.time-picker.clock-dial.container.size,
 md.comp.time-picker.clock-dial.label-text.text-style,

dev/tools/gen_defaults/lib/button_template.dart

@@ -125,6 +125,29 @@ class _${blockName}DefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize =>
+    const MaterialStatePropertyAll<double>(${getToken("$tokenGroup.with-icon.icon.size")});
+
+  @override
+  MaterialStateProperty<Color>? get iconColor {
+    return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
+      if (states.contains(MaterialState.disabled)) {
+        return ${color('$tokenGroup.with-icon.disabled.icon.color')}.withOpacity(${opacity("$tokenGroup.with-icon.disabled.icon.opacity")});
+      }
+      if (states.contains(MaterialState.pressed)) {
+        return ${color('$tokenGroup.with-icon.pressed.icon.color')};
+      }
+      if (states.contains(MaterialState.hovered)) {
+        return ${color('$tokenGroup.with-icon.hover.icon.color')};
+      }
+      if (states.contains(MaterialState.focused)) {
+        return ${color('$tokenGroup.with-icon.focus.icon.color')};
+      }
+      return ${color('$tokenGroup.with-icon.icon.color')};
+    });
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize =>
     const MaterialStatePropertyAll<Size>(Size.infinite);

dev/tools/gen_defaults/lib/menu_template.dart

@@ -121,6 +121,11 @@ class _MenuButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize {
+    return const MaterialStatePropertyAll<double>(${getToken("md.comp.list.list-item.leading-icon.size")});
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize {
     return ButtonStyleButton.allOrNull<Size>(Size.infinite);

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

@@ -162,22 +162,39 @@ abstract class ButtonStyleButton extends StatefulWidget {
   /// {@macro flutter.material.ButtonStyleButton.iconAlignment}
   final IconAlignment iconAlignment;
 
-  /// Returns a non-null [ButtonStyle] that's based primarily on the [Theme]'s
-  /// [ThemeData.textTheme] and [ThemeData.colorScheme].
+  /// Returns a [ButtonStyle] that's based primarily on the [Theme]'s
+  /// [ThemeData.textTheme] and [ThemeData.colorScheme], but has most values
+  /// filled out (non-null).
   ///
-  /// The returned style can be overridden by the [style] parameter and
-  /// by the style returned by [themeStyleOf]. For example the default
-  /// style of the [TextButton] subclass can be overridden with its
-  /// [TextButton.style] constructor parameter, or with a
-  /// [TextButtonTheme].
+  /// The returned style can be overridden by the [style] parameter and by the
+  /// style returned by [themeStyleOf] that some button-specific themes like
+  /// [TextButtonTheme] or [ElevatedButtonTheme] override. For example the
+  /// default style of the [TextButton] subclass can be overridden with its
+  /// [TextButton.style] constructor parameter, or with a [TextButtonTheme].
   ///
-  /// Concrete button subclasses should return a ButtonStyle that
-  /// has no null properties, and where all of the [WidgetStateProperty]
-  /// properties resolve to non-null values.
+  /// Concrete button subclasses should return a [ButtonStyle] with as many
+  /// non-null properties as possible, where all of the non-null
+  /// [WidgetStateProperty] properties resolve to non-null values.
+  ///
+  /// ## Properties that can be null
+  ///
+  /// Some properties, like [ButtonStyle.fixedSize] would override other values
+  /// in the same [ButtonStyle] if set, so they are allowed to be null.  Here is
+  /// a summary of properties that are allowed to be null when returned in the
+  /// [ButtonStyle] returned by this function, an why:
+  ///
+  /// - [ButtonStyle.fixedSize] because it would override other values in the
+  ///   same [ButtonStyle], like [ButtonStyle.maximumSize].
+  /// - [ButtonStyle.side] because null is a valid value for a button that has
+  ///   no side. [OutlinedButton] returns a non-null default for this, however.
+  /// - [ButtonStyle.backgroundBuilder] and [ButtonStyle.foregroundBuilder]
+  ///   because they would override the [ButtonStyle.foregroundColor] and
+  ///   [ButtonStyle.backgroundColor] of the same [ButtonStyle].
   ///
   /// See also:
   ///
-  ///  * [themeStyleOf], Returns the ButtonStyle of this button's component theme.
+  /// * [themeStyleOf], returns the ButtonStyle of this button's component
+  ///   theme.
   @protected
   ButtonStyle defaultStyleOf(BuildContext context);
 
@@ -479,7 +496,10 @@ class _ButtonStyleState extends State<ButtonStyleButton> with TickerProviderStat
           customBorder: resolvedShape.copyWith(side: resolvedSide),
           statesController: statesController,
           child: IconTheme.merge(
-            data: IconThemeData(color: resolvedIconColor ?? resolvedForegroundColor, size: resolvedIconSize),
+            data: IconThemeData(
+              color: resolvedIconColor ?? resolvedForegroundColor,
+              size: resolvedIconSize,
+            ),
             child: effectiveChild,
           ),
         ),

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

@@ -698,6 +698,29 @@ class _ElevatedButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize =>
+    const MaterialStatePropertyAll<double>(18.0);
+
+  @override
+  MaterialStateProperty<Color>? get iconColor {
+    return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
+      if (states.contains(MaterialState.disabled)) {
+        return _colors.onSurface.withOpacity(0.38);
+      }
+      if (states.contains(MaterialState.pressed)) {
+        return _colors.primary;
+      }
+      if (states.contains(MaterialState.hovered)) {
+        return _colors.primary;
+      }
+      if (states.contains(MaterialState.focused)) {
+        return _colors.primary;
+      }
+      return _colors.primary;
+    });
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize =>
     const MaterialStatePropertyAll<Size>(Size.infinite);

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

@@ -730,6 +730,29 @@ class _FilledButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize =>
+    const MaterialStatePropertyAll<double>(18.0);
+
+  @override
+  MaterialStateProperty<Color>? get iconColor {
+    return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
+      if (states.contains(MaterialState.disabled)) {
+        return _colors.onSurface.withOpacity(0.38);
+      }
+      if (states.contains(MaterialState.pressed)) {
+        return _colors.onPrimary;
+      }
+      if (states.contains(MaterialState.hovered)) {
+        return _colors.onPrimary;
+      }
+      if (states.contains(MaterialState.focused)) {
+        return _colors.onPrimary;
+      }
+      return _colors.onPrimary;
+    });
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize =>
     const MaterialStatePropertyAll<Size>(Size.infinite);
@@ -852,6 +875,29 @@ class _FilledTonalButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize =>
+    const MaterialStatePropertyAll<double>(18.0);
+
+  @override
+  MaterialStateProperty<Color>? get iconColor {
+    return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
+      if (states.contains(MaterialState.disabled)) {
+        return _colors.onSurface.withOpacity(0.38);
+      }
+      if (states.contains(MaterialState.pressed)) {
+        return _colors.onSecondaryContainer;
+      }
+      if (states.contains(MaterialState.hovered)) {
+        return _colors.onSecondaryContainer;
+      }
+      if (states.contains(MaterialState.focused)) {
+        return _colors.onSecondaryContainer;
+      }
+      return _colors.onSecondaryContainer;
+    });
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize =>
     const MaterialStatePropertyAll<Size>(Size.infinite);

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

@@ -3800,6 +3800,11 @@ class _MenuButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize {
+    return const MaterialStatePropertyAll<double>(24.0);
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize {
     return ButtonStyleButton.allOrNull<Size>(Size.infinite);

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

@@ -606,6 +606,29 @@ class _OutlinedButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize =>
+    const MaterialStatePropertyAll<double>(18.0);
+
+  @override
+  MaterialStateProperty<Color>? get iconColor {
+    return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
+      if (states.contains(MaterialState.disabled)) {
+        return _colors.onSurface.withOpacity(0.38);
+      }
+      if (states.contains(MaterialState.pressed)) {
+        return _colors.primary;
+      }
+      if (states.contains(MaterialState.hovered)) {
+        return _colors.primary;
+      }
+      if (states.contains(MaterialState.focused)) {
+        return _colors.primary;
+      }
+      return _colors.primary;
+    });
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize =>
     const MaterialStatePropertyAll<Size>(Size.infinite);

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

@@ -639,6 +639,29 @@ class _TextButtonDefaultsM3 extends ButtonStyle {
 
   // No default fixedSize
 
+  @override
+  MaterialStateProperty<double>? get iconSize =>
+    const MaterialStatePropertyAll<double>(18.0);
+
+  @override
+  MaterialStateProperty<Color>? get iconColor {
+    return MaterialStateProperty.resolveWith((Set<MaterialState> states) {
+      if (states.contains(MaterialState.disabled)) {
+        return _colors.onSurface.withOpacity(0.38);
+      }
+      if (states.contains(MaterialState.pressed)) {
+        return _colors.primary;
+      }
+      if (states.contains(MaterialState.hovered)) {
+        return _colors.primary;
+      }
+      if (states.contains(MaterialState.focused)) {
+        return _colors.primary;
+      }
+      return _colors.primary;
+    });
+  }
+
   @override
   MaterialStateProperty<Size>? get maximumSize =>
     const MaterialStatePropertyAll<Size>(Size.infinite);

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

@@ -775,6 +775,8 @@ class ToggleButtons extends StatelessWidget {
             style: ButtonStyle(
               backgroundColor: MaterialStatePropertyAll<Color?>(effectiveFillColor),
               foregroundColor: MaterialStatePropertyAll<Color?>(currentColor),
+              iconSize: const MaterialStatePropertyAll<double>(24.0),
+              iconColor: MaterialStatePropertyAll<Color?>(currentColor),
               overlayColor: _ToggleButtonDefaultOverlay(
                 selected:  onPressed != null && isSelected[index],
                 unselected: onPressed != null && !isSelected[index],

packages/flutter/test/material/button_style_test.dart

@@ -22,26 +22,30 @@ void main() {
 
   test('ButtonStyle defaults', () {
     const ButtonStyle style = ButtonStyle();
-    expect(style.textStyle, null);
-    expect(style.backgroundColor, null);
-    expect(style.foregroundColor, null);
-    expect(style.overlayColor, null);
-    expect(style.shadowColor, null);
-    expect(style.surfaceTintColor, null);
-    expect(style.elevation, null);
-    expect(style.padding, null);
-    expect(style.minimumSize, null);
-    expect(style.fixedSize, null);
-    expect(style.maximumSize, null);
-    expect(style.iconColor, null);
-    expect(style.iconSize, null);
-    expect(style.side, null);
-    expect(style.shape, null);
-    expect(style.mouseCursor, null);
-    expect(style.visualDensity, null);
-    expect(style.tapTargetSize, null);
-    expect(style.animationDuration, null);
-    expect(style.enableFeedback, null);
+    expect(style.textStyle, isNull);
+    expect(style.backgroundColor, isNull);
+    expect(style.foregroundColor, isNull);
+    expect(style.overlayColor, isNull);
+    expect(style.shadowColor, isNull);
+    expect(style.surfaceTintColor, isNull);
+    expect(style.elevation, isNull);
+    expect(style.padding, isNull);
+    expect(style.minimumSize, isNull);
+    expect(style.fixedSize, isNull);
+    expect(style.maximumSize, isNull);
+    expect(style.iconColor, isNull);
+    expect(style.iconSize, isNull);
+    expect(style.side, isNull);
+    expect(style.shape, isNull);
+    expect(style.mouseCursor, isNull);
+    expect(style.visualDensity, isNull);
+    expect(style.tapTargetSize, isNull);
+    expect(style.animationDuration, isNull);
+    expect(style.enableFeedback, isNull);
+    expect(style.alignment, isNull);
+    expect(style.splashFactory, isNull);
+    expect(style.backgroundBuilder, isNull);
+    expect(style.foregroundBuilder, isNull);
   });
 
   testWidgets('Default ButtonStyle debugFillProperties', (WidgetTester tester) async {

packages/flutter/test/material/elevated_button_test.dart

@@ -159,6 +159,114 @@ void main() {
     expect(material.type, MaterialType.button);
   });
 
+  testWidgets('ElevatedButton.defaultStyle produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final ElevatedButton button = ElevatedButton(
+      onPressed: () { },
+      child: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    // Enabled ElevatedButton
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.side, isNull, reason: 'side style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
+    testWidgets('ElevatedButton.defaultStyle with an icon produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final ElevatedButton button = ElevatedButton.icon(
+      onPressed: () { },
+      icon: const SizedBox(),
+      label: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.side, isNull, reason: 'side style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
   testWidgets('ElevatedButton.icon produces the correct widgets if icon is null', (WidgetTester tester) async {
     const ColorScheme colorScheme = ColorScheme.light();
     final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
@@ -409,6 +517,7 @@ void main() {
               data: ElevatedButtonThemeData(
                 style: ButtonStyle(
                   foregroundColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
+                  iconColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
                 ),
               ),
               child: Builder(
@@ -995,8 +1104,8 @@ void main() {
     expect(paddingRect.left, iconRect.left - 16);
     // Use the taller widget to check the top and bottom padding.
     final Rect tallerWidget = iconRect.height > labelRect.height ? iconRect : labelRect;
-    expect(paddingRect.top, tallerWidget.top - 5);
-    expect(paddingRect.bottom, tallerWidget.bottom + 12);
+    expect(paddingRect.top, closeTo(tallerWidget.top - 6.5, .01));
+    expect(paddingRect.bottom, closeTo(tallerWidget.bottom + 13.5, .01));
   });
 
   group('Default ElevatedButton padding for textScaleFactor, textDirection', () {

packages/flutter/test/material/filled_button_test.dart

@@ -127,6 +127,114 @@ void main() {
     await tester.pumpAndSettle();
   });
 
+  testWidgets('FilledButton.defaultStyle produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final FilledButton button = FilledButton(
+      onPressed: () { },
+      child: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    // Enabled FilledButton
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.side, isNull, reason: 'side style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
+    testWidgets('FilledButton.defaultStyle with an icon produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final FilledButton button = FilledButton.icon(
+      onPressed: () { },
+      icon: const SizedBox(),
+      label: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.side, isNull, reason: 'side style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
   testWidgets('FilledButton.icon produces the correct widgets if icon is null', (WidgetTester tester) async {
     const ColorScheme colorScheme = ColorScheme.light();
     final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
@@ -601,6 +709,7 @@ void main() {
               data: FilledButtonThemeData(
                 style: ButtonStyle(
                   foregroundColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
+                  iconColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
                 ),
               ),
               child: Builder(
@@ -1174,14 +1283,18 @@ void main() {
     final Rect labelRect = tester.getRect(find.byKey(labelKey));
     final Rect iconRect = tester.getRect(find.byType(Icon));
 
+    Matcher closeOnWeb(num value) {
+      return kIsWeb ? closeTo(value, 1e-2) : equals(value);
+    }
+
     // The right padding should be applied on the right of the label, whereas the
     // left padding should be applied on the left side of the icon.
-    expect(paddingRect.right, labelRect.right + 10);
-    expect(paddingRect.left, iconRect.left - 16);
+    expect(paddingRect.right, equals(labelRect.right + 10));
+    expect(paddingRect.left, equals(iconRect.left - 16));
     // Use the taller widget to check the top and bottom padding.
     final Rect tallerWidget = iconRect.height > labelRect.height ? iconRect : labelRect;
-    expect(paddingRect.top, tallerWidget.top - 5);
-    expect(paddingRect.bottom, tallerWidget.bottom + 12);
+    expect(paddingRect.top, closeOnWeb(tallerWidget.top - 6.5));
+    expect(paddingRect.bottom, closeOnWeb(tallerWidget.bottom + 13.5));
   });
 
   group('Default FilledButton padding for textScaleFactor, textDirection', () {

packages/flutter/test/material/outlined_button_test.dart

@@ -174,6 +174,114 @@ void main() {
     expect(material.type, MaterialType.button);
   });
 
+  testWidgets('OutlinedButton.defaultStyle produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final OutlinedButton button = OutlinedButton(
+      onPressed: () { },
+      child: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    // Enabled OutlinedButton
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+    expect(style.side, isNotNull, reason: 'side style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
+    testWidgets('OutlinedButton.defaultStyle with an icon produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final OutlinedButton button = OutlinedButton.icon(
+      onPressed: () { },
+      icon: const SizedBox(),
+      label: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+    expect(style.side, isNotNull, reason: 'side style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
   testWidgets('OutlinedButton.icon produces the correct widgets if icon is null', (WidgetTester tester) async {
     const ColorScheme colorScheme = ColorScheme.light();
     final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
@@ -600,7 +708,7 @@ void main() {
             child: OutlinedButton.icon(
               key: buttonKey,
               style: ButtonStyle(
-                foregroundColor: MaterialStateProperty.resolveWith<Color>(getIconColor),
+                iconColor: MaterialStateProperty.resolveWith<Color>(getIconColor),
               ),
               icon: const Icon(Icons.add),
               label: const Text('OutlinedButton'),

packages/flutter/test/material/text_button_test.dart

@@ -154,6 +154,114 @@ void main() {
     expect(material.type, MaterialType.button);
   });
 
+  testWidgets('TextButton.defaultStyle produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final TextButton button = TextButton(
+      onPressed: () { },
+      child: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    // Enabled TextButton
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.side, isNull, reason: 'side style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
+    testWidgets('TextButton.defaultStyle with an icon produces a ButtonStyle with appropriate non-null values', (WidgetTester tester) async {
+    const ColorScheme colorScheme = ColorScheme.light();
+    final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
+
+    final TextButton button = TextButton.icon(
+      onPressed: () { },
+      icon: const SizedBox(),
+      label: const Text('button'),
+    );
+    BuildContext? capturedContext;
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: Center(
+          child: Builder(
+            builder: (BuildContext context) {
+              capturedContext = context;
+              return button;
+            }
+          ),
+        ),
+      ),
+    );
+    final ButtonStyle style = button.defaultStyleOf(capturedContext!);
+
+    // Properties that must be non-null.
+    expect(style.textStyle, isNotNull, reason: 'textStyle style');
+    expect(style.backgroundColor, isNotNull, reason: 'backgroundColor style');
+    expect(style.foregroundColor, isNotNull, reason: 'foregroundColor style');
+    expect(style.overlayColor, isNotNull, reason: 'overlayColor style');
+    expect(style.shadowColor, isNotNull, reason: 'shadowColor style');
+    expect(style.surfaceTintColor, isNotNull, reason: 'surfaceTintColor style');
+    expect(style.elevation, isNotNull, reason: 'elevation style');
+    expect(style.padding, isNotNull, reason: 'padding style');
+    expect(style.minimumSize, isNotNull, reason: 'minimumSize style');
+    expect(style.maximumSize, isNotNull, reason: 'maximumSize style');
+    expect(style.iconColor, isNotNull, reason: 'iconColor style');
+    expect(style.iconSize, isNotNull, reason: 'iconSize style');
+    expect(style.shape, isNotNull, reason: 'shape style');
+    expect(style.mouseCursor, isNotNull, reason: 'mouseCursor style');
+    expect(style.visualDensity, isNotNull, reason: 'visualDensity style');
+    expect(style.tapTargetSize, isNotNull, reason: 'tapTargetSize style');
+    expect(style.animationDuration, isNotNull, reason: 'animationDuration style');
+    expect(style.enableFeedback, isNotNull, reason: 'enableFeedback style');
+    expect(style.alignment, isNotNull, reason: 'alignment style');
+    expect(style.splashFactory, isNotNull, reason: 'splashFactory style');
+
+    // Properties that are expected to be null.
+    expect(style.fixedSize, isNull, reason: 'fixedSize style');
+    expect(style.side, isNull, reason: 'side style');
+    expect(style.backgroundBuilder, isNull, reason: 'backgroundBuilder style');
+    expect(style.foregroundBuilder, isNull, reason: 'foregroundBuilder style');
+  });
+
   testWidgets('TextButton.icon produces the correct widgets when icon is null', (WidgetTester tester) async {
     const ColorScheme colorScheme = ColorScheme.light();
     final ThemeData theme = ThemeData.from(colorScheme: colorScheme);
@@ -463,6 +571,7 @@ void main() {
             child: TextButton.icon(
               style: ButtonStyle(
                 foregroundColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
+                iconColor: MaterialStateProperty.resolveWith<Color>(getTextColor),
               ),
               key: buttonKey,
               icon: const Icon(Icons.add),