Set modal bottom sheet barrier color (#45067)

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

@@ -344,6 +344,7 @@ class _ModalBottomSheetRoute<T> extends PopupRoute<T> {
     this.elevation,
     this.shape,
     this.clipBehavior,
+    this.modalBarrierColor,
     this.isDismissible = true,
     @required this.isScrollControlled,
     RouteSettings settings,
@@ -358,6 +359,7 @@ class _ModalBottomSheetRoute<T> extends PopupRoute<T> {
   final double elevation;
   final ShapeBorder shape;
   final Clip clipBehavior;
+  final Color modalBarrierColor;
   final bool isDismissible;
 
   @override
@@ -370,7 +372,7 @@ class _ModalBottomSheetRoute<T> extends PopupRoute<T> {
   final String barrierLabel;
 
   @override
-  Color get barrierColor => Colors.black54;
+  Color get barrierColor => modalBarrierColor ?? Colors.black54;
 
   AnimationController _animationController;
 
@@ -501,6 +503,7 @@ Future<T> showModalBottomSheet<T>({
   double elevation,
   ShapeBorder shape,
   Clip clipBehavior,
+  Color barrierColor,
   bool isScrollControlled = false,
   bool useRootNavigator = false,
   bool isDismissible = true,
@@ -523,6 +526,7 @@ Future<T> showModalBottomSheet<T>({
     shape: shape,
     clipBehavior: clipBehavior,
     isDismissible: isDismissible,
+    modalBarrierColor: barrierColor
   ));
 }
 

packages/flutter/test/material/bottom_sheet_test.dart

@@ -342,6 +342,7 @@ void main() {
     const double elevation = 9.0;
     final ShapeBorder shape = BeveledRectangleBorder(borderRadius: BorderRadius.circular(12));
     const Clip clipBehavior = Clip.antiAlias;
+    const Color barrierColor = Colors.red;
 
     await tester.pumpWidget(MaterialApp(
       home: Scaffold(
@@ -353,6 +354,7 @@ void main() {
     showModalBottomSheet<void>(
       context: scaffoldKey.currentContext,
       backgroundColor: color,
+      barrierColor: barrierColor,
       elevation: elevation,
       shape: shape,
       clipBehavior: clipBehavior,
@@ -371,6 +373,9 @@ void main() {
     expect(bottomSheet.elevation, elevation);
     expect(bottomSheet.shape, shape);
     expect(bottomSheet.clipBehavior, clipBehavior);
+
+    final ModalBarrier modalBarrier = tester.widget(find.byType(ModalBarrier).last);
+    expect(modalBarrier.color, barrierColor);
   });
 
   testWidgets('modal BottomSheet with scrollController has semantics', (WidgetTester tester) async {