Backport overlay security fix

    <uses-permission android:name="android.permission.KILL_UID" />

    <uses-permission android:name="android.permission.MANAGE_APP_OPS_RESTRICTIONS" />

    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <uses-permission android:name="android.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS" />

    <uses-permission android:name="com.google.android.permission.INSTALL_WEARABLE_PACKAGES" />

 */

package com.android.packageinstaller.permission.ui;

import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;

import android.app.Activity;

import android.app.AppOpsManager;

import android.os.Binder;

import android.os.IBinder;

import android.os.Bundle;

public class OverlayTouchActivity extends Activity {

    private final IBinder mToken = new Binder();

    @Override

    protected void onResume() {

        super.onResume();

        setOverlayAllowed(false);

    }

    @Override

    protected void onPause() {

        super.onPause();

        setOverlayAllowed(true);

    }

    private void setOverlayAllowed(boolean allowed) {

        AppOpsManager appOpsManager = getSystemService(AppOpsManager.class);

        if (appOpsManager != null) {

            appOpsManager.setUserRestriction(AppOpsManager.OP_SYSTEM_ALERT_WINDOW,

                    !allowed, mToken);

            appOpsManager.setUserRestriction(AppOpsManager.OP_TOAST_WINDOW,

                    !allowed, mToken);

        }

    protected void onCreate(Bundle savedInstanceState) {

        getWindow().addPrivateFlags(PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS);

        super.onCreate(savedInstanceState);

    }

}