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

base/power_monitor/power_monitor_android.h

Index: base/power_monitor/power_monitor_android.h
diff --git a/base/system_monitor/system_monitor_android.h b/base/power_monitor/power_monitor_android.h
similarity index 65%
rename from base/system_monitor/system_monitor_android.h
rename to base/power_monitor/power_monitor_android.h
index 9f60560fc9c20eb546cc66c4efc19c3d188ddd69..0859e83a4100fc3ba62d4363206d48c99e976946 100644
--- a/base/system_monitor/system_monitor_android.h
+++ b/base/power_monitor/power_monitor_android.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef BASE_SYSTEM_MONITOR_SYSTEM_MONITOR_ANDROID_H_
-#define BASE_SYSTEM_MONITOR_SYSTEM_MONITOR_ANDROID_H_
+#ifndef BASE_POWER_MONITOR_POWER_MONITOR_ANDROID_H_
+#define BASE_POWER_MONITOR_POWER_MONITOR_ANDROID_H_
 
 #include <jni.h>
 
@@ -14,4 +14,4 @@ bool RegisterSystemMonitor(JNIEnv* env);
 
 }  // namespace base
 
-#endif  // BASE_SYSTEM_MONITOR_SYSTEM_MONITOR_ANDROID_H_
+#endif  // BASE_POWER_MONITOR_POWER_MONITOR_ANDROID_H_