Support hot reload over websocket (#2616)

* renamed DWDS injector parameter

* updated chromeProxyService to perform hotreload with websockets

* updated changelog

* applied dart format

* remove newline in changelog

* updated error message

* implemented _performWebSocketFetchLibrariesForHotReload

* applied dart format

* reverted code to remove fetchLibrariesForHotReload websocket logic

* applied dart format

Author: jyameo

dwds/CHANGELOG.md

@@ -1,5 +1,8 @@
 ## 24.3.11-wip
 
+- Added WebSocket-based hot reload support: `reloadSources` in `ChromeProxyService` and `DevHandler` now handle hot reload requests and responses over WebSockets.
+- Refactored the injected client to use a reusable function for handling hot reload requests and responses over WebSockets.
+
 ## 24.3.10
 
 - Disabled breakpoints on changed files in a hot reload. They currently do not

dwds/lib/data/hot_reload_request.dart

@@ -0,0 +1,24 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library hot_reload_request;
+
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'hot_reload_request.g.dart';
+
+/// A request to hot reload the application.
+abstract class HotReloadRequest
+    implements Built<HotReloadRequest, HotReloadRequestBuilder> {
+  static Serializer<HotReloadRequest> get serializer =>
+      _$hotReloadRequestSerializer;
+
+  /// A unique identifier for this request.
+  String get id;
+
+  HotReloadRequest._();
+  factory HotReloadRequest([void Function(HotReloadRequestBuilder) updates]) =
+      _$HotReloadRequest;
+}

dwds/lib/data/hot_reload_request.g.dart

@@ -0,0 +1,31 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library hot_reload_response;
+
+import 'package:built_value/built_value.dart';
+import 'package:built_value/serializer.dart';
+
+part 'hot_reload_response.g.dart';
+
+/// A response to a hot reload request.
+abstract class HotReloadResponse
+    implements Built<HotReloadResponse, HotReloadResponseBuilder> {
+  static Serializer<HotReloadResponse> get serializer =>
+      _$hotReloadResponseSerializer;
+
+  /// The unique identifier matching the request.
+  String get id;
+
+  /// Whether the hot reload succeeded on the client.
+  bool get success;
+
+  /// An optional error message if success is false.
+  @BuiltValueField(wireName: 'error')
+  String? get errorMessage;
+
+  HotReloadResponse._();
+  factory HotReloadResponse([void Function(HotReloadResponseBuilder) updates]) =
+      _$HotReloadResponse;
+}