profiler: cleanup unused alternate_timer code

base/profiler/alternate_timer.h

-// Copyright (c) 2012 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.
-
-// This is a glue file, which allows third party code to call into our profiler
-// without having to include most any functions from base.
-
-#ifndef BASE_PROFILER_ALTERNATE_TIMER_H_
-#define BASE_PROFILER_ALTERNATE_TIMER_H_
-
-#include "base/base_export.h"
-
-namespace tracked_objects {
-
-enum TimeSourceType { TIME_SOURCE_TYPE_WALL_TIME };
-
-// Provide type for an alternate timer function.
-typedef unsigned int NowFunction();
-
-// Set an alternate timer function to replace the OS time function when
-// profiling.  Typically this is called by an allocator that is providing a
-// function that indicates how much memory has been allocated on any given
-// thread.
-BASE_EXPORT void SetAlternateTimeSource(NowFunction* now_function,
-                                        TimeSourceType type);
-
-// Gets the pointer to a function that was set via SetAlternateTimeSource().
-// Returns NULL if no set was done prior to calling GetAlternateTimeSource.
-NowFunction* GetAlternateTimeSource();
-
-// Returns the type of the currently set time source.
-BASE_EXPORT TimeSourceType GetTimeSourceType();
-
-}  // namespace tracked_objects
-
-#endif  // BASE_PROFILER_ALTERNATE_TIMER_H_