Migrate FloatingActionButton to Material 3 (#94486)

dev/tools/gen_defaults/data/material-tokens.json

 {
-  "version": "v0.72",
-  "date": "2021-12-16 00:27:25.239571",
+  "version": "v0.74",
+  "date": "2022-01-06",
   "md.sys.color.light.on-tertiary": "md.ref.palette.tertiary100",
   "md.sys.color.light.on-secondary-container": "md.ref.palette.secondary10",
   "md.sys.color.light.on-secondary": "md.ref.palette.secondary100",

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

@@ -43,6 +43,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
     this.highlightElevation,
     this.shape,
     this.enableFeedback,
+    this.iconSize,
     this.sizeConstraints,
     this.smallSizeConstraints,
     this.largeSizeConstraints,
@@ -103,6 +104,9 @@ class FloatingActionButtonThemeData with Diagnosticable {
   /// ignored.
   final bool? enableFeedback;
 
+  /// Overrides the default icon size for the [FloatingActionButton];
+  final double? iconSize;
+
   /// Overrides the default size constraints for the [FloatingActionButton].
   final BoxConstraints? sizeConstraints;
 
@@ -140,6 +144,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
     double? highlightElevation,
     ShapeBorder? shape,
     bool? enableFeedback,
+    double? iconSize,
     BoxConstraints? sizeConstraints,
     BoxConstraints? smallSizeConstraints,
     BoxConstraints? largeSizeConstraints,
@@ -161,6 +166,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
       highlightElevation: highlightElevation ?? this.highlightElevation,
       shape: shape ?? this.shape,
       enableFeedback: enableFeedback ?? this.enableFeedback,
+      iconSize: iconSize ?? this.iconSize,
       sizeConstraints: sizeConstraints ?? this.sizeConstraints,
       smallSizeConstraints: smallSizeConstraints ?? this.smallSizeConstraints,
       largeSizeConstraints: largeSizeConstraints ?? this.largeSizeConstraints,
@@ -193,6 +199,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
       highlightElevation: lerpDouble(a?.highlightElevation, b?.highlightElevation, t),
       shape: ShapeBorder.lerp(a?.shape, b?.shape, t),
       enableFeedback: t < 0.5 ? a?.enableFeedback : b?.enableFeedback,
+      iconSize: lerpDouble(a?.iconSize, b?.iconSize, t),
       sizeConstraints: BoxConstraints.lerp(a?.sizeConstraints, b?.sizeConstraints, t),
       smallSizeConstraints: BoxConstraints.lerp(a?.smallSizeConstraints, b?.smallSizeConstraints, t),
       largeSizeConstraints: BoxConstraints.lerp(a?.largeSizeConstraints, b?.largeSizeConstraints, t),
@@ -218,6 +225,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
       highlightElevation,
       shape,
       enableFeedback,
+      iconSize,
       sizeConstraints,
       smallSizeConstraints,
       largeSizeConstraints,
@@ -247,6 +255,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
         && other.highlightElevation == highlightElevation
         && other.shape == shape
         && other.enableFeedback == enableFeedback
+        && other.iconSize == iconSize
         && other.sizeConstraints == sizeConstraints
         && other.smallSizeConstraints == smallSizeConstraints
         && other.largeSizeConstraints == largeSizeConstraints
@@ -272,6 +281,7 @@ class FloatingActionButtonThemeData with Diagnosticable {
     properties.add(DoubleProperty('highlightElevation', highlightElevation, defaultValue: null));
     properties.add(DiagnosticsProperty<ShapeBorder>('shape', shape, defaultValue: null));
     properties.add(DiagnosticsProperty<bool>('enableFeedback', enableFeedback, defaultValue: null));
+    properties.add(DoubleProperty('iconSize', iconSize, defaultValue: null));
     properties.add(DiagnosticsProperty<BoxConstraints>('sizeConstraints', sizeConstraints, defaultValue: null));
     properties.add(DiagnosticsProperty<BoxConstraints>('smallSizeConstraints', smallSizeConstraints, defaultValue: null));
     properties.add(DiagnosticsProperty<BoxConstraints>('largeSizeConstraints', largeSizeConstraints, defaultValue: null));

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

@@ -1134,10 +1134,6 @@ class ThemeData with Diagnosticable {
   /// start using new colors, typography and other features of Material 3.
   /// If false, they will use the Material 2 look and feel.
   ///
-  /// Currently no components have been migrated to support Material 3.
-  /// As they are updated to include Material 3 support this documentation
-  /// will be modified to indicate exactly what widgets this flag will affect.
-  ///
   /// During the migration to Material 3, turning this on may yield
   /// inconsistent look and feel in your app. Some components will be migrated
   /// before others and typography changes will be coming in stages.
@@ -1148,6 +1144,10 @@ class ThemeData with Diagnosticable {
   /// all uses of it. Everything will use the Material 3 look and feel at
   /// that point.
   ///
+  /// Components that have been migrated to Material 3 are:
+  ///
+  ///   * [FloatingActionButton]
+  ///
   /// See also:
   ///
   ///   * [Material Design 3](https://m3.material.io/).

packages/flutter/test/material/floating_action_button_theme_test.dart

@@ -33,6 +33,8 @@ void main() {
     expect(_getRawMaterialButton(tester).shape, const CircleBorder());
     expect(_getRawMaterialButton(tester).splashColor, ThemeData().splashColor);
     expect(_getRawMaterialButton(tester).constraints, const BoxConstraints.tightFor(width: 56.0, height: 56.0));
+    expect(_getIconSize(tester).width, 24.0);
+    expect(_getIconSize(tester).height, 24.0);
   });
 
   testWidgets('FloatingActionButtonThemeData values are used when no FloatingActionButton properties are specified', (WidgetTester tester) async {
@@ -138,6 +140,7 @@ void main() {
 
   testWidgets('FloatingActionButton.small uses custom constraints when specified in the theme', (WidgetTester tester) async {
     const BoxConstraints constraints = BoxConstraints.tightFor(width: 100.0, height: 100.0);
+    const double iconSize = 24.0;
 
     await tester.pumpWidget(MaterialApp(
       theme: ThemeData().copyWith(
@@ -154,10 +157,13 @@ void main() {
     ));
 
     expect(_getRawMaterialButton(tester).constraints, constraints);
+    expect(_getIconSize(tester).width, iconSize);
+    expect(_getIconSize(tester).height, iconSize);
   });
 
   testWidgets('FloatingActionButton.large uses custom constraints when specified in the theme', (WidgetTester tester) async {
     const BoxConstraints constraints = BoxConstraints.tightFor(width: 100.0, height: 100.0);
+    const double iconSize = 36.0;
 
     await tester.pumpWidget(MaterialApp(
       theme: ThemeData().copyWith(
@@ -174,6 +180,8 @@ void main() {
     ));
 
     expect(_getRawMaterialButton(tester).constraints, constraints);
+    expect(_getIconSize(tester).width, iconSize);
+    expect(_getIconSize(tester).height, iconSize);
   });
 
   testWidgets('FloatingActionButton.extended uses custom properties when specified in the theme', (WidgetTester tester) async {
@@ -271,6 +279,7 @@ void main() {
       highlightElevation: 43,
       shape: BeveledRectangleBorder(),
       enableFeedback: true,
+      iconSize: 42,
       sizeConstraints: BoxConstraints.tightFor(width: 100.0, height: 100.0),
       smallSizeConstraints: BoxConstraints.tightFor(width: 101.0, height: 101.0),
       largeSizeConstraints: BoxConstraints.tightFor(width: 102.0, height: 102.0),
@@ -298,6 +307,7 @@ void main() {
       'highlightElevation: 43.0',
       'shape: BeveledRectangleBorder(BorderSide(Color(0xff000000), 0.0, BorderStyle.none), BorderRadius.zero)',
       'enableFeedback: true',
+      'iconSize: 42.0',
       'sizeConstraints: BoxConstraints(w=100.0, h=100.0)',
       'smallSizeConstraints: BoxConstraints(w=101.0, h=101.0)',
       'largeSizeConstraints: BoxConstraints(w=102.0, h=102.0)',
@@ -326,3 +336,15 @@ RichText _getRichText(WidgetTester tester) {
     ),
   );
 }
+
+SizedBox _getIconSize(WidgetTester tester) {
+  return tester.widget<SizedBox>(
+    find.descendant(
+      of: find.descendant(
+        of: find.byType(FloatingActionButton),
+        matching: find.byType(Icon),
+      ),
+      matching: find.byType(SizedBox),
+    ),
+  );
+}