profiler: cleanup unused alternate_timer code

base/profiler/alternate_timer.cc

Index: base/profiler/alternate_timer.cc
diff --git a/base/profiler/alternate_timer.cc b/base/profiler/alternate_timer.cc
deleted file mode 100644
index 14b4c348cac030e5d87ef552648a8c74c6e2e821..0000000000000000000000000000000000000000
--- a/base/profiler/alternate_timer.cc
+++ /dev/null
@@ -1,32 +0,0 @@
-// 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.
-
-#include "base/profiler/alternate_timer.h"
-
-namespace {
-
-tracked_objects::NowFunction* g_time_function = nullptr;
-tracked_objects::TimeSourceType g_time_source_type =
-    tracked_objects::TIME_SOURCE_TYPE_WALL_TIME;
-
-}  // anonymous namespace
-
-namespace tracked_objects {
-
-// Set an alternate timer function to replace the OS time function when
-// profiling.
-void SetAlternateTimeSource(NowFunction* now_function, TimeSourceType type) {
-  g_time_function = now_function;
-  g_time_source_type = type;
-}
-
-NowFunction* GetAlternateTimeSource() {
-  return g_time_function;
-}
-
-TimeSourceType GetTimeSourceType() {
-  return g_time_source_type;
-}
-
-}  // namespace tracked_objects