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

ui/views/win/hwnd_message_handler.cc

 // 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 "ui/views/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <shellapi.h>
 
 #include "base/bind.h"
-#include "base/system_monitor/system_monitor.h"
+#include "base/power_monitor/power_monitor.h"
 #include "base/win/windows_version.h"
 #include "ui/base/events/event.h"
 #include "ui/base/keycodes/keyboard_code_conversion_win.h"
 #include "ui/base/native_theme/native_theme_win.h"
 #include "ui/base/win/hwnd_util.h"
 #include "ui/base/win/mouse_wheel_util.h"
 #include "ui/base/win/shell.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/canvas_paint.h"
 #include "ui/gfx/canvas_skia_paint.h"
@@ skipping 1823 matching lines @@
 #endif
     }
   } else {
     // TODO(msw): Find a better solution for this crbug.com/93530 workaround.
     // Some scenarios otherwise fail to validate minimized app/popup windows.
     ValidateRect(hwnd(), NULL);
   }
 }
 
 LRESULT HWNDMessageHandler::OnPowerBroadcast(DWORD power_event, DWORD data) {
-  base::SystemMonitor* monitor = base::SystemMonitor::Get();
-  if (monitor)
-    monitor->ProcessWmPowerBroadcastMessage(power_event);
+  base::PowerMonitor* monitor = base::PowerMonitor::GetInstance();
+  monitor->ProcessWmPowerBroadcastMessage(power_event);
   SetMsgHandled(FALSE);
   return 0;
 }
 
 LRESULT HWNDMessageHandler::OnReflectedMessage(UINT message,
                                                WPARAM w_param,
                                                LPARAM l_param) {
   SetMsgHandled(FALSE);
   return 0;
 }
@@ skipping 224 matching lines @@
     DwmExtendFrameIntoClientArea(hwnd(), &m);
   }
   if (window_pos->flags & SWP_SHOWWINDOW)
     delegate_->HandleVisibilityChanged(true);
   else if (window_pos->flags & SWP_HIDEWINDOW)
     delegate_->HandleVisibilityChanged(false);
   SetMsgHandled(FALSE);
 }
 
 }  // namespace views