Remove the task tracking stuff in the bindings.

mojo/common/task_tracker.h

-// 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_COMMON_TASK_TRACKER_H_
-#define MOJO_COMMON_TASK_TRACKER_H_
-
-#include <stdint.h>
-
-namespace mojo {
-namespace common {
-
-class TaskTracker {
- public:
-  static intptr_t StartTracking(const char* function_name,
-                                const char* file_name,
-                                int line_number,
-                                const void* program_counter);
-  static void EndTracking(intptr_t id);
-  static void Enable();
-};
-
-}  // namespace common
-}  // namespace mojo
-
-#endif  // MOJO_COMMON_TASK_TRACKER_H_