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

base/base.gypi

Index: base/base.gypi
diff --git a/base/base.gypi b/base/base.gypi
index 06522495ef9f8a43b01860b57b2d4fd2e156b39b..2771f4acd6496b5c5c85c1a35688753b2fb399c5 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -292,6 +292,13 @@
           'port.h',
           'posix/unix_domain_socket.cc',
           'posix/unix_domain_socket.h',
+          'power_state_manager.cc',
+          'power_state_manager.h',
+          'power_state_manager_android.cc',
+          'power_state_manager_ios.mm',
+          'power_state_manager_mac.mm',
+          'power_state_manager_posix.cc',
+          'power_state_manager_win.cc',
           'process.h',
           'process_info.h',
           'process_info_mac.cc',
@@ -378,11 +385,6 @@
           'synchronization/waitable_event_win.cc',
           'system_monitor/system_monitor.cc',
           'system_monitor/system_monitor.h',
-          'system_monitor/system_monitor_android.cc',
-          'system_monitor/system_monitor_ios.mm',
-          'system_monitor/system_monitor_mac.mm',
-          'system_monitor/system_monitor_posix.cc',
-          'system_monitor/system_monitor_win.cc',
           'sys_byteorder.h',
           'sys_info.h',
           'sys_info_android.cc',
@@ -582,7 +584,7 @@
               'base_paths_posix.cc',
               'files/file_path_watcher_kqueue.cc',
               'files/file_path_watcher_stub.cc',
-              'system_monitor/system_monitor_posix.cc',
+              'power_state_manager_posix.cc',
             ],
             'sources/': [
               ['include', '^files/file_path_watcher_linux\\.cc$'],