Hide non-system overlay windows in RequestIgnoreBatteryOptimizations.

Add SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS to
SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS.

Bug: 182165099
Test: manual (test PoC)
Change-Id: Iddf697c1e8945f49c6222605c67f8f98e9c418a9

src/com/android/settings/fuelgauge/RequestIgnoreBatteryOptimizations.java

@@ -93,6 +93,13 @@ public class RequestIgnoreBatteryOptimizations extends AlertActivity implements
         setupAlert();
     }
 
+    @Override
+    protected void onStart() {
+        super.onStart();
+        getWindow().addSystemFlags(android.view.WindowManager.LayoutParams
+                .SYSTEM_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);
+    }
+
     @Override
     public void onClick(DialogInterface dialog, int which) {
         switch (which) {