Remove old web socket API.

sdk/lib/_internal/pub/lib/src/barback/barback_server.dart

Index: sdk/lib/_internal/pub/lib/src/barback/barback_server.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/barback_server.dart b/sdk/lib/_internal/pub/lib/src/barback/barback_server.dart
index db4158d51379f27c7a54cea6962b245a22383a07..611d62ff1931fc51a014003636d0b910dc222f19 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/barback_server.dart
+++ b/sdk/lib/_internal/pub/lib/src/barback/barback_server.dart
@@ -17,7 +17,6 @@ import '../log.dart' as log;
 import '../utils.dart';
 import 'base_server.dart';
 import 'build_environment.dart';
-import 'old_web_socket_api.dart';
 
 /// Callback for determining if an asset with [id] should be served or not.
 typedef bool AllowAsset(AssetId id);
@@ -95,13 +94,6 @@ class BarbackServer extends BaseServer<BarbackServerResult> {
 
   /// Handles an HTTP request.
   void handleRequest(HttpRequest request) {
-    // TODO(rnystrom): Remove this when the Editor is using the admin server.
-    // port. See #17640.
-    if (WebSocketTransformer.isUpgradeRequest(request)) {
-      _handleWebSocket(request);
-      return;
-    }
-
     if (request.method != "GET" && request.method != "HEAD") {
       methodNotAllowed(request);
       return;
@@ -162,20 +154,6 @@ class BarbackServer extends BaseServer<BarbackServerResult> {
     });
   }
 
-  // TODO(rnystrom): Remove this when the Editor is using the admin server.
-  // port. See #17640.
-  /// Creates a web socket for [request] which should be an upgrade request.
-  void _handleWebSocket(HttpRequest request) {
-    Chain.track(WebSocketTransformer.upgrade(request)).then((socket) {
-      _webSockets.add(socket);
-      var api = new OldWebSocketApi(socket, environment);
-
-      return api.listen().whenComplete(() {
-        _webSockets.remove(api);
-      });
-    }).catchError(addError);
-  }
-
   /// Serves the body of [asset] on [request]'s response stream.
   ///
   /// Returns a future that completes when the response has been succesfully