emoji [nfc]: Move popularEmojiCandidates implementation down out of mixin

Author: chrisbobbe

lib/model/emoji.dart

@@ -115,9 +115,7 @@ mixin EmojiStore {
   ///
   /// See description in the web code:
   ///   https://github.com/zulip/zulip/blob/83a121c7e/web/shared/src/typeahead.ts#L3-L21
-  Iterable<EmojiCandidate> popularEmojiCandidates() {
-    return EmojiStoreImpl._popularCandidates;
-  }
+  Iterable<EmojiCandidate> popularEmojiCandidates();
 
   Iterable<EmojiCandidate> allEmojiCandidates();
 
@@ -237,6 +235,11 @@ class EmojiStoreImpl extends PerAccountStoreBase with EmojiStore {
     ];
   }
 
+  @override
+  Iterable<EmojiCandidate> popularEmojiCandidates() {
+    return _popularCandidates;
+  }
+
   /// Codes for the popular emoji, in order; all are Unicode emoji.
   // This list should match web:
   //   https://github.com/zulip/zulip/blob/83a121c7e/web/shared/src/typeahead.ts#L22-L29

lib/model/store.dart

@@ -611,6 +611,9 @@ class PerAccountStore extends PerAccountStoreBase with ChangeNotifier, EmojiStor
     notifyListeners();
   }
 
+  @override
+  Iterable<EmojiCandidate> popularEmojiCandidates() => _emoji.popularEmojiCandidates();
+
   @override
   Iterable<EmojiCandidate> allEmojiCandidates() => _emoji.allEmojiCandidates();