Updated gallery light and dark themes (#28619)

examples/flutter_gallery/lib/gallery/themes.dart

@@ -25,15 +25,19 @@ TextTheme _buildTextTheme(TextTheme base) {
 ThemeData _buildDarkTheme() {
   const Color primaryColor = Color(0xFF0175c2);
   const Color secondaryColor = Color(0xFF13B9FD);
-  final ThemeData base = ThemeData.dark();
   final ColorScheme colorScheme = const ColorScheme.dark().copyWith(
     primary: primaryColor,
     secondary: secondaryColor,
   );
-  return base.copyWith(
+  final ThemeData base = ThemeData(
+    brightness: Brightness.dark,
+    accentColorBrightness: Brightness.dark,
     primaryColor: primaryColor,
+    primaryColorDark: const Color(0xFF0050a0),
+    primaryColorLight: secondaryColor,
     buttonColor: primaryColor,
     indicatorColor: Colors.white,
+    toggleableActiveColor: const Color(0xFF6997DF),
     accentColor: secondaryColor,
     canvasColor: const Color(0xFF202124),
     scaffoldBackgroundColor: const Color(0xFF202124),
@@ -43,6 +47,8 @@ ThemeData _buildDarkTheme() {
       colorScheme: colorScheme,
       textTheme: ButtonTextTheme.primary,
     ),
+  );
+  return base.copyWith(
     textTheme: _buildTextTheme(base.textTheme),
     primaryTextTheme: _buildTextTheme(base.primaryTextTheme),
     accentTextTheme: _buildTextTheme(base.accentTextTheme),
@@ -56,12 +62,14 @@ ThemeData _buildLightTheme() {
     primary: primaryColor,
     secondary: secondaryColor,
   );
-  final ThemeData base = ThemeData.light();
-  return base.copyWith(
+  final ThemeData base = ThemeData(
+    brightness: Brightness.light,
+    accentColorBrightness: Brightness.dark,
     colorScheme: colorScheme,
     primaryColor: primaryColor,
     buttonColor: primaryColor,
     indicatorColor: Colors.white,
+    toggleableActiveColor: const Color(0xFF1E88E5),
     splashColor: Colors.white24,
     splashFactory: InkRipple.splashFactory,
     accentColor: secondaryColor,
@@ -73,6 +81,8 @@ ThemeData _buildLightTheme() {
       colorScheme: colorScheme,
       textTheme: ButtonTextTheme.primary,
     ),
+  );
+  return base.copyWith(
     textTheme: _buildTextTheme(base.textTheme),
     primaryTextTheme: _buildTextTheme(base.primaryTextTheme),
     accentTextTheme: _buildTextTheme(base.accentTextTheme),