document protocol for updating dart_style

DEPS

 # Copyright (c) 2012, 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.
 
 # IMPORTANT:
 # Before adding or updating dependencies, please review the documentation here:
 # https://github.com/dart-lang/sdk/wiki/Adding-and-Updating-Dependencies
 
 vars = {
   # The dart_root is the root of our sdk checkout. This is normally
@@ skipping 47 matching lines @@
   "charcode_tag": "@v1.1.1",
   "chrome_rev" : "@19997",
   "cli_util_tag" : "@0.1.0",
   "code_transformers_tag": "@v0.5.1",
   "collection_tag": "@1.13.0",
   "convert_tag": "@2.0.1",
   "crypto_tag" : "@2.0.1",
   "csslib_tag" : "@0.13.3+1",
   "dart2js_info_tag" : "@0.5.4+2",
   "dart_services_rev" : "@7aea2574e6f3924bf409a80afb8ad52aa2be4f97",
-  "dart_style_tag": "@1.0.7",
+
+  # Note: updates to dart_style have to be coordinated carefully with
+  # the infrastructure-team so that the internal formatter in
+  # `sdk/tools/sdks/*/dart-sdk/bin/dartfmt` matches the version here.
+  #
+  # Please follow this process to make updates:
+  #   * file an issue with area-infrastructure requesting a roll for this
+  #     package (please also indicate what version to roll).
+  #   * let the infrastructure team submit the change on your behalf,
+  #     so they can build a new dev release and roll the submitted sdks a few
+  #     minutes later.
+  #
+  # For more details, see https://github.com/dart-lang/sdk/issues/30164
+  "dart_style_tag": "@1.0.7",  # Please see the note above before updating.
+
   "dartdoc_tag" : "@v0.13.0+1",
   "fixnum_tag": "@0.10.5",
   "func_tag": "@1.0.0",
   "glob_tag": "@1.1.3",
   "html_tag" : "@0.13.1",
   "http_multi_server_tag" : "@2.0.3",
   "http_parser_tag" : "@3.1.1",
   "http_tag" : "@0.11.3+13",
   "http_throttle_tag" : "@1.0.1",
   "idl_parser_rev": "@7fbe68cab90c38147dee4f48c30ad0d496c17915",
@@ skipping 408 matching lines @@
     # Update the Windows toolchain if necessary.
     'name': 'win_toolchain',
     'pattern': '.',
     'action': ['python', 'sdk/build/vs_toolchain.py', 'update'],
   },
   {
     "pattern": ".",
     "action": ["python", Var("dart_root") + "/tools/generate_buildfiles.py"],
   },
 ]