compose_box: Add BuildContext context arg to buildTopicInput

Author: chungwwei

lib/widgets/compose_box.dart

@@ -1435,7 +1435,7 @@ abstract class _ComposeBoxBody extends StatelessWidget {
 
   ComposeBoxController get controller;
 
-  Widget? buildTopicInput();
+  Widget? buildTopicInput(BuildContext context);
   Widget buildContentInput();
   bool getComposeButtonsEnabled(BuildContext context);
   Widget? buildSendButton();
@@ -1471,7 +1471,7 @@ abstract class _ComposeBoxBody extends StatelessWidget {
       _AttachFromCameraButton(controller: controller, enabled: composeButtonsEnabled),
     ];
 
-    final topicInput = buildTopicInput();
+    final topicInput = buildTopicInput(context);
     final sendButton = buildSendButton();
     return Column(children: [
       Padding(
@@ -1509,7 +1509,7 @@ class _StreamComposeBoxBody extends _ComposeBoxBody {
   @override
   final StreamComposeBoxController controller;
 
-  @override Widget buildTopicInput() => _TopicInput(
+  @override Widget? buildTopicInput(BuildContext context) => _TopicInput(
     streamId: narrow.streamId,
     controller: controller,
   );
@@ -1537,7 +1537,7 @@ class _FixedDestinationComposeBoxBody extends _ComposeBoxBody {
   @override
   final FixedDestinationComposeBoxController controller;
 
-  @override Widget? buildTopicInput() => null;
+  @override Widget? buildTopicInput(BuildContext context) => null;
 
   @override Widget buildContentInput() => _FixedDestinationContentInput(
     narrow: narrow,
@@ -1562,7 +1562,7 @@ class _EditMessageComposeBoxBody extends _ComposeBoxBody {
   @override
   final EditMessageComposeBoxController controller;
 
-  @override Widget? buildTopicInput() => null;
+  @override Widget? buildTopicInput(BuildContext context) => null;
 
   @override Widget buildContentInput() => _EditMessageContentInput(
     narrow: narrow,