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

base/power_monitor/power_monitor_ios.mm

Index: base/power_monitor/power_monitor_ios.mm
diff --git a/base/system_monitor/system_monitor_ios.mm b/base/power_monitor/power_monitor_ios.mm
similarity index 91%
rename from base/system_monitor/system_monitor_ios.mm
rename to base/power_monitor/power_monitor_ios.mm
index f3251b60f143c0b119fdcce7323dedab2e60be5f..a875dd08883f0b1db2e711d4922a99babead4f29 100644
--- a/base/system_monitor/system_monitor_ios.mm
+++ b/base/power_monitor/power_monitor_ios.mm
@@ -2,13 +2,13 @@
 // 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"
+#include "base/power_monitor/power_monitor.h"
 
 #import <UIKit/UIKit.h>
 
 namespace base {
 
-void SystemMonitor::PlatformInit() {
+void PowerMonitor::PlatformInit() {
   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
   id foreground =
       [nc addObserverForName:UIApplicationWillEnterForegroundNotification
@@ -28,7 +28,7 @@ void SystemMonitor::PlatformInit() {
   notification_observers_.push_back(background);
 }
 
-void SystemMonitor::PlatformDestroy() {
+void PowerMonitor::PlatformDestroy() {
   NSNotificationCenter* nc = [NSNotificationCenter defaultCenter];
   for (std::vector<id>::iterator it = notification_observers_.begin();
        it != notification_observers_.end(); ++it) {