[federated_plugin] adds web implementation of federated_plugin (#507)

experimental/federated_plugin/federated_plugin_web/test_driver/federated_plugin_web_e2e.dart

@@ -0,0 +1,53 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:html';
+
+import 'package:e2e/e2e.dart';
+import 'package:federated_plugin_web/federated_plugin_web.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mockito/mockito.dart';
+
+const kLatitude = 4;
+const kLongitude = 3;
+
+class GeoLocationMock extends Mock implements Geolocation {}
+
+class GeoPositionMock extends Mock implements Geoposition {
+  @override
+  Coordinates get coords => MockCoordinates();
+}
+
+class MockCoordinates extends Mock implements Coordinates {
+  @override
+  num get latitude => kLatitude;
+
+  @override
+  num get longitude => kLongitude;
+}
+
+void main() {
+  E2EWidgetsFlutterBinding.ensureInitialized();
+
+  group('FederatedPlugin test', () {
+    final geoLocationMock = GeoLocationMock();
+
+    setUp(() {
+      when(geoLocationMock.getCurrentPosition())
+          .thenAnswer((realInvocation) async => GeoPositionMock());
+    });
+
+    testWidgets('getLocation Method', (tester) async {
+      final federatedPlugin = FederatedPlugin(geolocation: geoLocationMock);
+      final location = await federatedPlugin.getLocation();
+
+      // Verify that getCurrentPosition was called.
+      verify(geoLocationMock.getCurrentPosition());
+
+      // Verify the values of Location.longitude and Location.latitude.
+      expect(location.longitude, kLongitude);
+      expect(location.latitude, kLatitude);
+    });
+  });
+}

experimental/federated_plugin/federated_plugin_web/test_driver/federated_plugin_web_e2e_test.dart

@@ -0,0 +1,9 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:e2e/e2e_driver.dart' as e2e;
+
+Future<void> main() async => e2e.main();