protected override void SetState(FrameNavigation.Parameter navigationParameter, FrameNavigation.Parameter stateParameter)
{
var protocolFilter = new HttpBaseProtocolFilter();
foreach (var cookie in protocolFilter.CookieManager.GetCookies(new Uri("https://oauth.vk.com")))
{
protocolFilter.CookieManager.DeleteCookie(cookie);
}
WebView.Source = VkAuthorization.GetOAuthUri();
}