How to reset QQuickView and his QML file into initial state?

[Robotex]

Looks. Here is the simplest code: "https://www.dropbox.com/s/ctdcgrk0eqgq3a3/webview_test.tar.gz":https://www.dropbox.com/s/ctdcgrk0eqgq3a3/webview_test.tar.gz

When you start this app you will see white window. Click on window and you will see browser with Twitter. Click again and browser will be hide and destroyed.

So, please login to Twitter, than destroy browser by clicking first window and then create it again by clicking on first window. You will see that you left signed in. But I need that browser every time opens without signed user (even if user checked "Remember me" checkbox). How to do this? How to reset browser to the initial state?

Here is main parts of project:

main.cpp

@ #include <QApplication>
#include <QQuickView>

#include "container.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    Container c;
    c.start();

    return a.exec();
}@

container.cpp
@
#include "container.h"

#include <QDebug>
#include <QQuickItem>
#include <QQmlContext>

Container::Container(QObject *parent) :
    QObject(parent)
{
    mainFile = new QQuickView();

    browserExists = false;
}

Container::~Container()
{
    delete mainFile;
}

void Container::start()
{
    mainFile->setSource(QUrl("qrc:/main.qml"));

    connect(mainFile->rootObject(), SIGNAL(click()), this, SLOT(mainFileClicked()));

    mainFile->show();
}

void Container::mainFileClicked()
{
    if(!browserExists)
    {
        browser = new QQuickView();
        browser->setSource(QUrl("qrc:/browser.qml"));
        browser->rootContext()->setContextProperty("address", "http://twitter.com");

        browser->show();

        browserExists = true;
    }
    else
    {
        browser->hide();
        delete browser;

        browserExists = false;
    }
}@

main.qml

@ import QtQuick 2.0

Rectangle {
    width: 320
    height: 240

    signal click();

    MouseArea {
        anchors.fill: parent

        onClicked:
        {
            click()
        }
    }
}@

browser.qml
@
import QtQuick 2.0
import QtWebKit 3.0
import QtWebKit.experimental 1.0

Item {
    width: 640
    height: 480

    signal closeWindow();

    WebView
    {
        anchors.fill: parent
        url: address
        experimental.preferences.privateBrowsingEnabled: true
    }
}@