SystemMonitor refactoring: move power state monitor into a separate class called PowerMonitor

base/system_monitor/system_monitor_posix.cc

Index: base/system_monitor/system_monitor_posix.cc
diff --git a/base/system_monitor/system_monitor_posix.cc b/base/system_monitor/system_monitor_posix.cc
deleted file mode 100644
index 6cf01bfee85f6b9e8c71fa5f784c1dc56541ce80..0000000000000000000000000000000000000000
--- a/base/system_monitor/system_monitor_posix.cc
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2011 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/system_monitor/system_monitor.h"
-
-namespace base {
-
-bool SystemMonitor::IsBatteryPower() {
-  NOTIMPLEMENTED();
-  return false;
-}
-
-}  // namespace base