notif: Add createNotificationChannel method to pigeon bindings

See: https://developer.android.com/reference/androidx/core/app/NotificationManagerCompat#createNotificationChannel(androidx.core.app.NotificationChannelCompat)

Author: rajveermalviya

lib/notifications/display.dart

@@ -53,16 +53,14 @@ class NotificationChannelManager {
   //    channel ID and delete it.  See zulip-mobile's `createNotificationChannel`
   //    in android/app/src/main/java/com/zulipmobile/notifications/NotificationChannelManager.kt .
   static Future<void> _ensureChannel() async {
-    final plugin = ZulipBinding.instance.notifications;
-    await plugin.resolvePlatformSpecificImplementation<AndroidFlutterLocalNotificationsPlugin>()
-      ?.createNotificationChannel(AndroidNotificationChannel(
-        kChannelId,
-        'Messages', // TODO(i18n)
-        importance: Importance.high,
-        enableLights: true,
-        vibrationPattern: kVibrationPattern,
-        // TODO(#340) sound
-      ));
+    await ZulipBinding.instance.androidNotificationHost.createNotificationChannel(NotificationChannel(
+      id: kChannelId,
+      name: 'Messages', // TODO(i18n)
+      importance: NotificationImportance.high,
+      lightsEnabled: true,
+      vibrationPattern: kVibrationPattern,
+      // TODO(#340) sound
+    ));
   }
 }
 

test/model/binding.dart

@@ -578,10 +578,20 @@ class FakeIOSFlutterLocalNotificationsPlugin extends Fake implements IOSFlutterL
 }
 
 class FakeAndroidNotificationHostApi implements AndroidNotificationHostApi {
+  /// Consume the log of calls made to [createNotificationChannel].
+  ///
+  /// This returns a list of the arguments to all calls made
+  /// to [createNotificationChannel] since the last call to this method.
+  List<NotificationChannel> takeCreatedChannels() {
+    final result = _createdChannels;
+    _createdChannels = [];
+    return result;
+  }
+  List<NotificationChannel> _createdChannels = [];
+
   @override
-  Future<void> createNotificationChannel(NotificationChannel channel) {
-    // TODO: implement createNotificationChannel
-    throw UnimplementedError();
+  Future<void> createNotificationChannel(NotificationChannel channel) async {
+    _createdChannels.add(channel);
   }
 
   /// Consume the log of calls made to [notify].

test/notifications/display_test.dart

@@ -90,20 +90,13 @@ void main() {
   group('NotificationChannelManager', () {
     test('smoke', () async {
       await init();
-      check(notifAndroid.takeCreatedChannels()).single
+      check(testBinding.androidNotificationHost.takeCreatedChannels()).single
         ..id.equals(NotificationChannelManager.kChannelId)
         ..name.equals('Messages')
-        ..description.isNull()
-        ..groupId.isNull()
-        ..importance.equals(Importance.high)
-        ..playSound.isTrue()
-        ..sound.isNull()
-        ..enableVibration.isTrue()
+        ..importance.equals(NotificationImportance.high)
+        ..lightsEnabled.equals(true)
         ..vibrationPattern.isNotNull().deepEquals(
             NotificationChannelManager.kVibrationPattern)
-        ..showBadge.isTrue()
-        ..enableLights.isTrue()
-        ..ledColor.isNull()
       ;
     });
   });
@@ -462,19 +455,12 @@ void main() {
   });
 }
 
-extension AndroidNotificationChannelChecks on Subject<AndroidNotificationChannel> {
+extension NotificationChannelChecks on Subject<NotificationChannel> {
   Subject<String> get id => has((x) => x.id, 'id');
-  Subject<String> get name => has((x) => x.name, 'name');
-  Subject<String?> get description => has((x) => x.description, 'description');
-  Subject<String?> get groupId => has((x) => x.groupId, 'groupId');
-  Subject<Importance> get importance => has((x) => x.importance, 'importance');
-  Subject<bool> get playSound => has((x) => x.playSound, 'playSound');
-  Subject<AndroidNotificationSound?> get sound => has((x) => x.sound, 'sound');
-  Subject<bool> get enableVibration => has((x) => x.enableVibration, 'enableVibration');
-  Subject<bool> get enableLights => has((x) => x.enableLights, 'enableLights');
+  Subject<int> get importance => has((x) => x.importance, 'importance');
+  Subject<String?> get name => has((x) => x.name, 'name');
+  Subject<bool?> get lightsEnabled => has((x) => x.lightsEnabled, 'lightsEnabled');
   Subject<Int64List?> get vibrationPattern => has((x) => x.vibrationPattern, 'vibrationPattern');
-  Subject<Color?> get ledColor => has((x) => x.ledColor, 'ledColor');
-  Subject<bool> get showBadge => has((x) => x.showBadge, 'showBadge');
 }
 
 extension on Subject<AndroidNotificationHostApiNotifyCall> {