Remove the task tracking stuff in the bindings.

mojo/public/cpp/environment/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("../../mojo_sdk.gni")
 
 mojo_sdk_source_set("environment") {
   sources = [
     "async_waiter.h",
     "environment.h",
     "logging.h",
-    "task_tracker.h",
   ]
 
   mojo_sdk_public_deps = [ "mojo/public/c/environment" ]
 
   mojo_sdk_deps = [
     "mojo/public/cpp/bindings:callback",
     "mojo/public/cpp/system",
   ]
 }
 
 mojo_sdk_source_set("standalone") {
   sources = [
     "lib/async_waiter.cc",
     "lib/default_async_waiter.cc",
     "lib/default_async_waiter.h",
     "lib/default_logger.cc",
     "lib/default_logger.h",
-    "lib/default_task_tracker.cc",
-    "lib/default_task_tracker.h",
     "lib/environment.cc",
     "lib/logging.cc",
-    "lib/scoped_task_tracking.cc",
-    "lib/scoped_task_tracking.h",
   ]
 
   public_deps = [
     ":environment",
   ]
 
   mojo_sdk_deps = [
     "mojo/public/c/environment",
     "mojo/public/cpp/system",
     "mojo/public/cpp/utility",
   ]
 }
 
 # This is an implementation of Environment, which can be used instead of
 # :standalone, that provides only logging and has no external dependencies.
 mojo_sdk_source_set("logging_only") {
   sources = [
     "lib/default_logger.cc",
     "lib/default_logger.h",
     "lib/logging.cc",
     "lib/logging_only_environment.cc",
   ]
 
   public_deps = [
     ":environment",
   ]
 }