Delete the tracing service

services/service_manager/standalone/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//services/service_manager/public/cpp/service.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 source_set("standalone") {
   sources = [
     "context.cc",
     "context.h",
-    "tracer.cc",
-    "tracer.h",
   ]
 
   deps = [
     "//base",
     "//base/third_party/dynamic_annotations",
     "//components/tracing:startup_tracing",
     "//mojo/common:common_base",
     "//mojo/edk/system",
     "//services/catalog:lib",
     "//services/service_manager",
     "//services/service_manager/public/cpp",
     "//services/service_manager/public/cpp/standalone_service",
     "//services/service_manager/runner/common",
     "//services/service_manager/runner/host:lib",
-    "//services/tracing/public/cpp",
-    "//services/tracing/public/interfaces",
     "//url",
   ]
 }