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

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

Index: sdk/lib/_internal/pub_generated/lib/src/barback/base_server.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/base_server.dart b/sdk/lib/_internal/pub_generated/lib/src/barback/base_server.dart
similarity index 82%
copy from sdk/lib/_internal/pub/lib/src/barback/base_server.dart
copy to sdk/lib/_internal/pub_generated/lib/src/barback/base_server.dart
index a47b362f962efc7d9e9e08f33c1d5d8a0e0781d1..e95c5d37f6ed8f8f031708b7eb0be79ae840f8d6 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/base_server.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/barback/base_server.dart
@@ -42,9 +42,10 @@ abstract class BaseServer<T> {
   final _resultsController = new StreamController<T>.broadcast();
 
   BaseServer(this.environment, this._server) {
-    shelf_io.serveRequests(_server, const shelf.Pipeline()
-        .addMiddleware(shelf.createMiddleware(errorHandler: _handleError))
-        .addHandler(handleRequest));
+    shelf_io.serveRequests(
+        _server,
+        const shelf.Pipeline().addMiddleware(
+            shelf.createMiddleware(errorHandler: _handleError)).addHandler(handleRequest));
   }
 
   /// Closes this server.
@@ -58,9 +59,12 @@ abstract class BaseServer<T> {
   /// Returns a 405 response to [request].
   shelf.Response methodNotAllowed(shelf.Request request) {
     logRequest(request, "405 Method Not Allowed");
-    return new shelf.Response(405,
+    return new shelf.Response(
+        405,
         body: "The ${request.method} method is not allowed for ${request.url}.",
-        headers: {'Allow': 'GET, HEAD'});
+        headers: {
+      'Allow': 'GET, HEAD'
+    });
   }
 
   /// Returns a 404 response to [request].
@@ -82,9 +86,10 @@ abstract class BaseServer<T> {
         <h1>404 Not Found</h1>""");
 
     if (asset != null) {
-      body.writeln("<p>Could not find asset "
-          "<code>${HTML_ESCAPE.convert(asset.path)}</code> in package "
-          "<code>${HTML_ESCAPE.convert(asset.package)}</code>.</p>");
+      body.writeln(
+          "<p>Could not find asset "
+              "<code>${HTML_ESCAPE.convert(asset.path)}</code> in package "
+              "<code>${HTML_ESCAPE.convert(asset.package)}</code>.</p>");
     }
 
     if (error != null) {
@@ -96,13 +101,14 @@ abstract class BaseServer<T> {
 
     // Force a UTF-8 encoding so that error messages in non-English locales are
     // sent correctly.
-    return new shelf.Response.notFound(body.toString(),
-        headers: {'Content-Type': 'text/html; charset=utf-8'});
+    return new shelf.Response.notFound(body.toString(), headers: {
+      'Content-Type': 'text/html; charset=utf-8'
+    });
   }
 
   /// Log [message] at [log.Level.FINE] with metadata about [request].
   void logRequest(shelf.Request request, String message) =>
-    log.fine("$this ${request.method} ${request.url}\n$message");
+      log.fine("$this ${request.method} ${request.url}\n$message");
 
   /// Adds [result] to the server's [results] stream.
   void addResult(T result) {