Remove the task tracking stuff in the bindings.

mojo/public/cpp/environment/lib/default_task_tracker.h

Index: mojo/public/cpp/environment/lib/default_task_tracker.h
diff --git a/mojo/public/cpp/environment/lib/default_task_tracker.h b/mojo/public/cpp/environment/lib/default_task_tracker.h
deleted file mode 100644
index 7a0c06478c6fe0afffb1368542fab3355c9fb1f1..0000000000000000000000000000000000000000
--- a/mojo/public/cpp/environment/lib/default_task_tracker.h
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2015 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.
-
-#ifndef MOJO_PUBLIC_CPP_ENVIRONMENT_LIB_DEFAULT_TASK_TRACKER_H_
-#define MOJO_PUBLIC_CPP_ENVIRONMENT_LIB_DEFAULT_TASK_TRACKER_H_
-
-namespace mojo {
-
-struct TaskTracker;
-
-namespace internal {
-
-extern const TaskTracker kDefaultTaskTracker;
-
-}  // namespace internal
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_ENVIRONMENT_LIB_DEFAULT_TASK_TRACKER_H_