[Slider] Rebase. (#52663)

dev/integration_tests/flutter_gallery/lib/demo/material/slider_demo.dart

@@ -69,6 +69,7 @@ class _CustomRangeThumbShape extends RangeSliderThumbShape {
     @required SliderThemeData sliderTheme,
     TextDirection textDirection,
     Thumb thumb,
+    bool isPressed,
   }) {
     final Canvas canvas = context.canvas;
     final ColorTween colorTween = ColorTween(
@@ -130,6 +131,8 @@ class _CustomThumbShape extends SliderComponentShape {
     SliderThemeData sliderTheme,
     TextDirection textDirection,
     double value,
+    double textScaleFactor,
+    Size sizeWithOverflow,
   }) {
     final Canvas canvas = context.canvas;
     final ColorTween colorTween = ColorTween(
@@ -169,6 +172,8 @@ class _CustomValueIndicatorShape extends SliderComponentShape {
     SliderThemeData sliderTheme,
     TextDirection textDirection,
     double value,
+    double textScaleFactor,
+    Size sizeWithOverflow,
   }) {
     final Canvas canvas = context.canvas;
     final ColorTween enableColor = ColorTween(
@@ -268,15 +273,21 @@ class _SlidersState extends State<_Sliders> {
                   ),
                 ),
               ),
-              Slider.adaptive(
-                value: _continuousValue,
-                min: 0.0,
-                max: 100.0,
-                onChanged: (double value) {
-                  setState(() {
-                    _continuousValue = value;
-                  });
-                },
+              SliderTheme(
+                data: const SliderThemeData(
+                  showValueIndicator: ShowValueIndicator.always,
+                ),
+                child: Slider.adaptive(
+                  label: _continuousValue.toStringAsFixed(6).toString(),
+                  value: _continuousValue,
+                  min: 0.0,
+                  max: 100.0,
+                  onChanged: (double value) {
+                    setState(() {
+                      _continuousValue = value;
+                    });
+                  },
+                ),
               ),
               const Text('Continuous with Editable Numerical Value'),
             ],
@@ -314,7 +325,7 @@ class _SlidersState extends State<_Sliders> {
                   activeTrackColor: Colors.deepPurple,
                   inactiveTrackColor: theme.colorScheme.onSurface.withOpacity(0.5),
                   activeTickMarkColor: theme.colorScheme.onSurface.withOpacity(0.7),
-                  inactiveTickMarkColor:  theme.colorScheme.surface.withOpacity(0.7),
+                  inactiveTickMarkColor: theme.colorScheme.surface.withOpacity(0.7),
                   overlayColor: theme.colorScheme.onSurface.withOpacity(0.12),
                   thumbColor: Colors.deepPurple,
                   valueIndicatorColor: Colors.deepPurpleAccent,

dev/integration_tests/flutter_gallery/lib/gallery/themes.dart

@@ -21,10 +21,12 @@ ThemeData _buildDarkTheme() {
   final ColorScheme colorScheme = const ColorScheme.dark().copyWith(
     primary: primaryColor,
     secondary: secondaryColor,
+    onPrimary: secondaryColor,
   );
   final ThemeData base = ThemeData(
     brightness: Brightness.dark,
     accentColorBrightness: Brightness.dark,
+    colorScheme: colorScheme,
     primaryColor: primaryColor,
     primaryColorDark: const Color(0xFF0050a0),
     primaryColorLight: secondaryColor,

packages/flutter/test/painting/system_fonts_test.dart

@@ -169,7 +169,10 @@ void main() {
         (ByteData data) { },
     );
     final RenderObject renderObject = tester.renderObject(find.byType(RangeSlider));
-    expect(renderObject.debugNeedsLayout, isTrue);
+
+    bool sliderBoxNeedsLayout;
+    renderObject.visitChildren((RenderObject child) {sliderBoxNeedsLayout = child.debugNeedsLayout;});
+    expect(sliderBoxNeedsLayout, isTrue);
   });
 
   testWidgets('Slider relayout upon system fonts changes', (WidgetTester tester) async {
@@ -191,8 +194,11 @@ void main() {
       SystemChannels.system.codec.encodeMessage(data),
         (ByteData data) { },
     );
-    final RenderObject renderObject = tester.renderObject(find.byType(Slider));
-    expect(renderObject.debugNeedsLayout, isTrue);
+     final RenderObject renderObject = tester.renderObject(find.byType(Slider));
+
+     bool sliderBoxNeedsLayout;
+     renderObject.visitChildren((RenderObject child) {sliderBoxNeedsLayout = child.debugNeedsLayout;});
+     expect(sliderBoxNeedsLayout, isTrue);
   });
 
   testWidgets('TimePicker relayout upon system fonts changes', (WidgetTester tester) async {