Removed MaterialApp accentColor dependency. (#77652)

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

@@ -678,7 +678,7 @@ class _MaterialScrollBehavior extends ScrollBehavior {
         return GlowingOverscrollIndicator(
           child: child,
           axisDirection: axisDirection,
-          color: Theme.of(context).accentColor,
+          color: Theme.of(context).colorScheme.secondary,
         );
     }
   }

packages/flutter/test/material/app_test.dart

@@ -9,6 +9,8 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 
+import '../rendering/mock_canvas.dart';
+
 class StateMarker extends StatefulWidget {
   const StateMarker({ Key? key, this.child }) : super(key: key);
 
@@ -882,6 +884,37 @@ void main() {
     expect(themeAfterBrightnessChange!.brightness, Brightness.dark);
   });
 
+  testWidgets('MaterialApp provides default overscroll color', (WidgetTester tester) async {
+    Future<void> slowDrag(WidgetTester tester, Offset start, Offset offset) async {
+      final TestGesture gesture = await tester.startGesture(start);
+      for (int index = 0; index < 10; index += 1) {
+        await gesture.moveBy(offset);
+        await tester.pump(const Duration(milliseconds: 20));
+      }
+      await gesture.up();
+    }
+
+    // The overscroll color should be a transparent version of the colorScheme's
+    // secondary color.
+    const Color secondaryColor = Color(0xff008800);
+    final Color glowSecondaryColor = secondaryColor.withOpacity(0.05);
+    final ThemeData theme = ThemeData.from(
+      colorScheme: const ColorScheme.light().copyWith(secondary: secondaryColor),
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: theme,
+        home: const SingleChildScrollView(
+          child: SizedBox(height: 2000.0),
+        ),
+      ),
+    );
+
+    final RenderObject painter = tester.renderObject(find.byType(CustomPaint).first);
+    await slowDrag(tester, const Offset(200.0, 200.0), const Offset(0.0, 5.0));
+    expect(painter, paints..circle(color: glowSecondaryColor));
+  });
+
   testWidgets('MaterialApp can customize initial routes', (WidgetTester tester) async {
     final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();
     await tester.pumpWidget(