chore: upgrade ChannelHeaderTheme

packages/stream_chat_flutter/lib/src/stream_chat_theme.dart

@@ -188,10 +188,10 @@ class StreamChatThemeData {
   /// Theme configuration for the [UserListView] widget.
   final UserListViewThemeData userListViewTheme;
 
-  /// Theme configuration for the [] widget.
+  /// Theme configuration for the [MessageSearchListView] widget.
   final MessageSearchListViewThemeData messageSearchListViewTheme;
 
-  /// Theme configuration for the [] widget.
+  /// Theme configuration for the [UserAvatar] widget.
   final AvatarThemeData avatarTheme;
 
   /// Creates a copy of [StreamChatThemeData] with specified attributes
@@ -279,7 +279,7 @@ class StreamChatThemeData {
     final iconTheme =
         IconThemeData(color: colorTheme.textHighEmphasis.withOpacity(.5));
     final channelTheme = ChannelTheme(
-      channelHeaderTheme: ChannelHeaderTheme(
+      channelHeaderTheme: ChannelHeaderThemeData(
         avatarTheme: AvatarThemeData(
           borderRadius: BorderRadius.circular(20),
           constraints: const BoxConstraints.tightFor(
@@ -497,7 +497,7 @@ class StreamChatThemeData {
         backgroundColor: colorTheme.appBg,
       ),
       avatarTheme: AvatarThemeData(
-        borderRadius: BorderRadius.circular(8),
+        borderRadius: BorderRadius.circular(20),
       ),
     );
   }

packages/stream_chat_flutter/lib/src/theme/channel_header_theme.dart

@@ -1,10 +1,64 @@
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
+import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 import 'package:stream_chat_flutter/src/theme/avatar_theme.dart';
 
-/// Theme for [ChannelHeader]
+/// Overrides the default style of [ChannelHeader] descendants.
-class ChannelHeaderTheme {
+///
-  /// Constructor for creating a [ChannelHeaderTheme]
+/// See also:
+///
+///  * [ChannelHeaderThemeData], which is used to configure this theme.
+class ChannelHeaderTheme extends InheritedTheme {
+  /// Creates a [ChannelHeaderTheme].
+  ///
+  /// The [data] parameter must not be null.
   const ChannelHeaderTheme({
+    Key? key,
+    required this.data,
+    required Widget child,
+  }) : super(key: key, child: child);
+
+  /// The configuration of this theme.
+  final ChannelHeaderThemeData data;
+
+  /// The closest instance of this class that encloses the given context.
+  ///
+  /// If there is no enclosing [ChannelHeaderTheme] widget, then
+  /// [StreamChatThemeData.channelTheme.channelHeaderTheme] is used.
+  ///
+  /// Typical usage is as follows:
+  ///
+  /// ```dart
+  /// final theme = ChannelHeaderTheme.of(context);
+  /// ```
+  static ChannelHeaderThemeData of(BuildContext context) {
+    final channelHeaderTheme =
+        context.dependOnInheritedWidgetOfExactType<ChannelHeaderTheme>();
+    return channelHeaderTheme?.data ??
+        StreamChatTheme.of(context).channelTheme.channelHeaderTheme;
+  }
+
+  @override
+  Widget wrap(BuildContext context, Widget child) =>
+      ChannelHeaderTheme(data: data, child: child);
+
+  @override
+  bool updateShouldNotify(ChannelHeaderTheme oldWidget) =>
+      data != oldWidget.data;
+}
+
+/// A style that overrides the default appearance of [ChannelHeader]s when used
+/// with [ChannelHeaderTheme] or with the overall [StreamChatTheme]'s
+/// [StreamChatThemeData.channelHeaderTheme].
+///
+/// See also:
+///
+/// * [ChannelHeaderTheme], the theme which is configured with this class.
+/// * [StreamChatThemeData.channelHeaderTheme], which can be used to override
+/// the default style for [ChannelHeader]s below the overall [StreamChatTheme].
+class ChannelHeaderThemeData with Diagnosticable {
+  /// Creates a [ChannelHeaderThemeData]
+  const ChannelHeaderThemeData({
     this.title,
     this.subtitle,
     this.avatarTheme,
@@ -20,25 +74,25 @@ class ChannelHeaderTheme {
   /// Theme for avatar
   final AvatarThemeData? avatarTheme;
 
-  /// Color for [ChannelHeaderTheme]
+  /// Color for [ChannelHeaderThemeData]
   final Color? color;
 
   /// Copy with theme
-  ChannelHeaderTheme copyWith({
+  ChannelHeaderThemeData copyWith({
     TextStyle? title,
     TextStyle? subtitle,
     AvatarThemeData? avatarTheme,
     Color? color,
   }) =>
-      ChannelHeaderTheme(
+      ChannelHeaderThemeData(
         title: title ?? this.title,
         subtitle: subtitle ?? this.subtitle,
         avatarTheme: avatarTheme ?? this.avatarTheme,
         color: color ?? this.color,
       );
 
-  /// Merge with other [ChannelHeaderTheme]
+  /// Merge with other [ChannelHeaderThemeData]
-  ChannelHeaderTheme merge(ChannelHeaderTheme? other) {
+  ChannelHeaderThemeData merge(ChannelHeaderThemeData? other) {
     if (other == null) return this;
     return copyWith(
       title: title?.merge(other.title) ?? other.title,

packages/stream_chat_flutter/lib/src/theme/channel_theme.dart

@@ -8,11 +8,11 @@ class ChannelTheme {
   });
 
   /// Theme of the [ChannelHeader] widget
-  final ChannelHeaderTheme channelHeaderTheme;
+  final ChannelHeaderThemeData channelHeaderTheme;
 
   /// Creates a copy of [ChannelTheme] with specified attributes overridden.
   ChannelTheme copyWith({
-    ChannelHeaderTheme? channelHeaderTheme,
+    ChannelHeaderThemeData? channelHeaderTheme,
   }) =>
       ChannelTheme(
         channelHeaderTheme: channelHeaderTheme ?? this.channelHeaderTheme,