Store the async-await compiled pub code directly in the repo.

utils/pub/pub.gyp

 # Copyright (c) 2013, 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.
 
 {
   'targets': [
     {
       'target_name': 'pub',
       'type': 'none',
       'dependencies': [
@@ skipping 11 matching lines @@
             '../../sdk/lib/_internal/libraries.dart',
             '<(SHARED_INTERMEDIATE_DIR)/pub_files.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/dart2js_files.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/pkg_files.stamp',
             '<(SHARED_INTERMEDIATE_DIR)/pub_packages.stamp',
           ],
           'outputs': [
             '<(SHARED_INTERMEDIATE_DIR)/pub.dart.snapshot',
           ],
           'action': [
-            'python',
-            '../../tools/create_pub_snapshot.py',
             '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
-            '../../sdk/lib/_internal/pub/bin/async_compile.dart',
-            '<(PRODUCT_DIR)/pub_packages/',
-            '<(SHARED_INTERMEDIATE_DIR)',
-          ],
+            '--package-root=<(PRODUCT_DIR)/pub_packages/',
+            '--snapshot=<(SHARED_INTERMEDIATE_DIR)/pub.dart.snapshot',
+            '../../sdk/lib/_internal/pub_generated/bin/pub.dart',
+          ]
         },
       ],
     },
     {
       'target_name': 'core_stubs',
       'type': 'none',
       'dependencies': [
         '../../runtime/dart-runtime.gyp:dart',
         '../../pkg/pkg.gyp:pkg_packages',
         '../../pkg/pkg_files.gyp:pkg_files_stamp'
@@ skipping 40 matching lines @@
             'python', '../../tools/create_timestamp_file.py',
             '<@(_outputs)',
           ],
         },
       ],
     }
 
 
   ],
 }