[Modify] Polish it

websocket-sharp/HttpRequest.cs

@@ -45,6 +45,7 @@ namespace WebSocketSharp
   {
     #region Private Fields
 
+    private CookieCollection _cookies;
     private string           _method;
     private string           _uri;
     private bool             _websocketRequest;
@@ -86,7 +87,10 @@ namespace WebSocketSharp
 
     public CookieCollection Cookies {
       get {
-        return Headers.GetCookies (false);
+        if (_cookies == null)
+          _cookies = Headers.GetCookies (false);
+
+        return _cookies;
       }
     }
 

websocket-sharp/Net/WebSockets/TcpListenerWebSocketContext.cs

@@ -52,7 +52,6 @@ namespace WebSocketSharp.Net.WebSockets
   {
     #region Private Fields
 
-    private CookieCollection    _cookies;
     private Logger              _log;
     private NameValueCollection _queryString;
     private HttpRequest         _request;
@@ -132,7 +131,7 @@ namespace WebSocketSharp.Net.WebSockets
     /// </value>
     public override CookieCollection CookieCollection {
       get {
-        return _cookies ?? (_cookies = _request.Cookies);
+        return _request.Cookies;
       }
     }