This DEP hasn't been touched in 2 years – can't see any uses

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 45 matching lines @@
   "boringssl_gen_rev": "@753224969dbe43dad29343146529727b5066c0f3",
   "boringssl_rev" : "@d519bf6be0b447fb80fbc539d4bff4479b5482a2",
   "charcode_tag": "@v1.1.1",
   "chrome_rev" : "@19997",
   "cli_util_tag" : "@0.1.0",
   "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",
 
   # 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
@@ skipping 126 matching lines @@
   Var("dart_root") + "/third_party/pkg/cli_util":
       (Var("github_mirror") % "cli_util") + Var("cli_util_tag"),
   Var("dart_root") + "/third_party/pkg/collection":
       (Var("github_mirror") % "collection") + Var("collection_tag"),
   Var("dart_root") + "/third_party/pkg/convert":
       (Var("github_mirror") % "convert") + Var("convert_tag"),
   Var("dart_root") + "/third_party/pkg/crypto":
       (Var("github_mirror") % "crypto") + Var("crypto_tag"),
   Var("dart_root") + "/third_party/pkg/csslib":
       (Var("github_mirror") % "csslib") + Var("csslib_tag"),
-  Var("dart_root") + "/third_party/dart-services":
-      (Var("github_mirror") % "dart-services") +
-      Var("dart_services_rev"),
   Var("dart_root") + "/third_party/pkg_tested/dart_style":
       (Var("github_mirror") % "dart_style") + Var("dart_style_tag"),
   Var("dart_root") + "/third_party/pkg/dart2js_info":
       (Var("github_mirror") % "dart2js_info") + Var("dart2js_info_tag"),
   Var("dart_root") + "/third_party/pkg/dartdoc":
       (Var("github_mirror") % "dartdoc") + Var("dartdoc_tag"),
   Var("dart_root") + "/third_party/pkg/fixnum":
       (Var("github_mirror") % "fixnum") + Var("fixnum_tag"),
   Var("dart_root") + "/third_party/pkg/func":
       (Var("github_mirror") % "func") + Var("func_tag"),
@@ skipping 255 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"],
   },
 ]