CefSharp 提供删除Cookie的方法，使用ICookieManager接口中的DeleteCookiesAsync方法
///
/// Deletes all cookies that matches all the provided parameters asynchronously. If both and are empty, all cookies will be deleted.
///
///The cookie URL. If an empty string is provided, any URL will be matched.
///The name of the cookie. If an empty string is provided, any URL will be matched.
/// A task that represents the delete operation. The value of the TResult parameter contains false if a non-empty invalid URL is specified, or if cookies cannot be accessed; otherwise, true.
Task DeleteCookiesAsync(string url, string name);
具体应用：Cef.GetGlobalCookieManager().DeleteCookiesAsync(string url, string name);
以上方法在应用过程中发现有问题，例如：当删除指定url=”http://www.codebye.com”的cookie时，不能完全将cookie 完全删除，只删除了一部分，对下次取cookie造成重复。
经过查看源码发现可以使用替代方案，cef_cookie.h中有描述（红色部分）：
///
// Delete all cookies that match the specified parameters. If both |url| and
// |cookie_name| values are specified all host and domain cookies matching
// both will be deleted. If only |url| is specified all host cookies (but not
// domain cookies) irrespective of path will be deleted. If |url| is empty all
// cookies for all hosts and domains will be deleted. If |callback| is
// non-NULL it will be executed asnychronously on the IO thread after the
// cookies have been deleted. Returns false if a non-empty invalid URL is
// specified or if cookies cannot be accessed. Cookies can alternately be
// deleted using the Visit*Cookies() methods.
///
/*–cef(optional_param=url,optional_param=cookie_name,
optional_param=callback)–*/
virtual bool DeleteCookies(const CefString& url,
const CefString& cookie_name,
CefRefPtr<CefDeleteCookiesCallback> callback) =0;
具体实现是使用CefCookieVisitor中的visit方法的第三个参数，方法说明：
///
// Method that will be called once for each cookie. |count| is the 0-based
// index for the current cookie. |total| is the total number of cookies.
// Set |deleteCookie| to true to delete the cookie currently being visited.
// Return false to stop visiting cookies. This method may never be called if
// no cookies are found.
///
/*–cef()–*/
virtual bool Visit(const CefCookie& cookie, int count, int total,
bool& deleteCookie) =0;
