[infra] Begin removing gyp

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': [
-        '../../runtime/dart-runtime.gyp:dart',
-        '../../pkg/pkg_files.gyp:pkg_files_stamp',
-        '../../utils/compiler/compiler.gyp:dart2js_files_stamp'
-      ],
-      'actions': [
-        {
-          'action_name': 'generate_pub_snapshot',
-          'inputs': [
-            '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
-            '../../sdk/lib/_internal/sdk_library_metadata/lib/libraries.dart',
-            '<(SHARED_INTERMEDIATE_DIR)/dart2js_files.stamp',
-            '<(SHARED_INTERMEDIATE_DIR)/pkg_files.stamp',
-          ],
-          'outputs': [
-            '<(SHARED_INTERMEDIATE_DIR)/pub.dart.snapshot',
-          ],
-          'action': [
-            '<(PRODUCT_DIR)/<(EXECUTABLE_PREFIX)dart<(EXECUTABLE_SUFFIX)',
-            '--packages=../../.packages',
-            '--snapshot=<(SHARED_INTERMEDIATE_DIR)/pub.dart.snapshot',
-            '../../third_party/pkg/pub/bin/pub.dart',
-          ]
-        },
-      ],
-    },
-  ],
-}