Revert "Use native async/await support in pub."

sdk/lib/_internal/pub_generated/lib/src/barback/admin_server.dart

Index: sdk/lib/_internal/pub_generated/lib/src/barback/admin_server.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/admin_server.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/admin_server.dart
similarity index 85%
copy from sdk/lib/_internal/pub/lib/src/barback/admin_server.dart
copy to sdk/lib/_internal/pub_generated/lib/src/barback/admin_server.dart
index 057a5888e91435ccca26a10c131a025d0e40b7f1..36bb621e5799764d4552fa943452486e7ab62aec 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/admin_server.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/barback/admin_server.dart
@@ -27,8 +27,8 @@ class AdminServer extends BaseServer {
   shelf.Handler _handler;
 
   /// Creates a new server and binds it to [port] of [host].
-  static Future<AdminServer> bind(AssetEnvironment environment,
-      String host, int port) {
+  static Future<AdminServer> bind(AssetEnvironment environment, String host,
+      int port) {
     return bindServer(host, port).then((server) {
       log.fine('Bound admin server to $host:$port.');
       return new AdminServer._(environment, server);
@@ -37,9 +37,8 @@ class AdminServer extends BaseServer {
 
   AdminServer._(AssetEnvironment environment, HttpServer server)
       : super(environment, server) {
-    _handler = new shelf.Cascade()
-        .add(webSocketHandler(_handleWebSocket))
-        .add(_handleHttp).handler;
+    _handler = new shelf.Cascade().add(
+        webSocketHandler(_handleWebSocket)).add(_handleHttp).handler;
   }
 
   /// Closes the server and all Web Socket connections.
@@ -56,7 +55,8 @@ class AdminServer extends BaseServer {
     // TODO(rnystrom): Actually respond to requests once there is an admin
     // interface. See #16954.
     logRequest(request, "501 Not Implemented");
-    return new shelf.Response(501,
+    return new shelf.Response(
+        501,
         body: "Currently this server only accepts Web Socket connections.");
   }
 
@@ -64,8 +64,7 @@ class AdminServer extends BaseServer {
   void _handleWebSocket(CompatibleWebSocket socket) {
     _webSockets.add(socket);
     var api = new WebSocketApi(socket, environment);
-    api.listen()
-        .whenComplete(() => _webSockets.remove(api))
-        .catchError(addError);
+    api.listen().whenComplete(
+        () => _webSockets.remove(api)).catchError(addError);
   }
 }