narrow [nfc]: Make containsMessage support MessageBase

Author: PIG208

lib/model/narrow.dart

@@ -19,7 +19,7 @@ sealed class Narrow {
   /// This does not necessarily mean the message list would show this message
   /// when navigated to this narrow; in particular it does not address the
   /// question of whether the stream or topic, or the sending user, is muted.
-  bool containsMessage(Message message);
+  bool containsMessage(MessageBase message);
 
   /// This narrow, expressed as an [ApiNarrow].
   ApiNarrow apiEncode();
@@ -47,7 +47,7 @@ class CombinedFeedNarrow extends Narrow {
   const CombinedFeedNarrow();
 
   @override
-  bool containsMessage(Message message) {
+  bool containsMessage(MessageBase message) {
     return true;
   }
 
@@ -71,8 +71,9 @@ class ChannelNarrow extends Narrow {
   final int streamId;
 
   @override
-  bool containsMessage(Message message) {
-    return message is StreamMessage && message.streamId == streamId;
+  bool containsMessage(MessageBase message) {
+    final destination = message.destination;
+    return destination is StreamDestination && destination.streamId == streamId;
   }
 
   @override
@@ -105,9 +106,10 @@ class TopicNarrow extends Narrow implements SendableNarrow {
   TopicNarrow sansWith() => TopicNarrow(streamId, topic);
 
   @override
-  bool containsMessage(Message message) {
-    return (message is StreamMessage
-      && message.streamId == streamId && message.topic == topic);
+  bool containsMessage(MessageBase message) {
+    final destination = message.destination;
+    return destination is StreamDestination
+      && destination.streamId == streamId && destination.topic == topic;
   }
 
   @override
@@ -262,11 +264,12 @@ class DmNarrow extends Narrow implements SendableNarrow {
   late final String _key = otherRecipientIds.join(',');
 
   @override
-  bool containsMessage(Message message) {
-    if (message is! DmMessage) return false;
-    if (message.destination.userIds.length != allRecipientIds.length) return false;
+  bool containsMessage(MessageBase message) {
+    final destination = message.destination;
+    if (destination is! DmDestination) return false;
+    if (destination.userIds.length != allRecipientIds.length) return false;
     int i = 0;
-    for (final userId in message.destination.userIds) {
+    for (final userId in destination.userIds) {
       if (userId != allRecipientIds[i]) return false;
       i++;
     }
@@ -306,7 +309,8 @@ class MentionsNarrow extends Narrow {
   const MentionsNarrow();
 
   @override
-  bool containsMessage(Message message) {
+  bool containsMessage(MessageBase message) {
+    if (message is! Message) return false;
     return message.flags.any((flag) {
       switch (flag) {
         case MessageFlag.mentioned:
@@ -345,7 +349,8 @@ class StarredMessagesNarrow extends Narrow {
   ApiNarrow apiEncode() => [ApiNarrowIs(IsOperand.starred)];
 
   @override
-  bool containsMessage(Message message) {
+  bool containsMessage(MessageBase message) {
+    if (message is! Message) return false;
     return message.flags.contains(MessageFlag.starred);
   }