Fix an exception in BatterMonitorFactory

device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorFactory.java

Index: device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorFactory.java
diff --git a/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorFactory.java b/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorFactory.java
index d17e2869a72c80124779f5977cf90c28875424d3..0d38e8b63b4fe3eb1808c719fef1b90817b0347f 100644
--- a/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorFactory.java
+++ b/device/battery/android/java/src/org/chromium/device/battery/BatteryMonitorFactory.java
@@ -13,7 +13,9 @@ import org.chromium.device.BatteryStatus;
 import org.chromium.device.battery.BatteryStatusManager.BatteryStatusCallback;
 import org.chromium.services.service_manager.InterfaceFactory;
 
+import java.util.ArrayList;
 import java.util.HashSet;
+import java.util.List;
 
 /**
  * Factory that creates instances of BatteryMonitor implementations and notifies them about battery
@@ -33,7 +35,8 @@ public class BatteryMonitorFactory implements InterfaceFactory<BatteryMonitor> {
         public void onBatteryStatusChanged(BatteryStatus batteryStatus) {
             ThreadUtils.assertOnUiThread();
 
-            for (BatteryMonitorImpl monitor : mSubscribedMonitors) {
+            List<BatteryMonitorImpl> monitors = new ArrayList<>(mSubscribedMonitors);
+            for (BatteryMonitorImpl monitor : monitors) {
                 monitor.didChange(batteryStatus);
             }
         }