Update feedback from Flutter team

Author: mvanbeusekom

packages/camera/lib/camera.dart

@@ -301,6 +301,9 @@ class CameraController extends ValueNotifier<CameraValue> {
   /// Whether to include audio when recording a video.
   final bool enableAudio;
 
+  /// True after [CameraController.dispose] has completed successfully.
+  bool get isDisposed => _isDisposed;
+
   int _textureId;
   bool _isDisposed = false;
   StreamSubscription<dynamic> _eventSubscription;

packages/camera/test/camera_test.dart

@@ -0,0 +1,34 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:camera/camera.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+void main() {
+  test("isDisposed true when disposed", () {
+    final MockCameraDescription description = MockCameraDescription();
+    final CameraController controller = CameraController(
+      description,
+      ResolutionPreset.low,
+    );
+
+    controller.dispose();
+    expect(controller.isDisposed, isTrue);
+  });
+
+  test("isDisposed false when not disposed", () {
+    final MockCameraDescription description = MockCameraDescription();
+    final CameraController controller = CameraController(
+      description,
+      ResolutionPreset.low,
+    );
+
+    expect(controller.isDisposed, isFalse);
+  });
+}
+
+class MockCameraDescription extends CameraDescription {
+  @override
+  String get name => 'back';
+}