Piwik\Plugins\CoreHome\Menu::configureTopMenu PHP Method

    public function configureTopMenu(MenuTop $menu)
    {
        $module = $this->getLoginModule();
        if (Piwik::isUserIsAnonymous()) {
            $menu->registerMenuIcon('Login_LogIn', 'icon-sign-in');
            $menu->addItem('Login_LogIn', null, array('module' => $module, 'action' => false), 1000, Piwik::translate('Login_LogIn'));
        } else {
            $menu->registerMenuIcon('General_Logout', 'icon-sign-out');
            $menu->addItem('General_Logout', null, array('module' => $module, 'action' => 'logout', 'idSite' => null), 1000, Piwik::translate('General_Logout'));
        }
    }