Remember if a user declines to provide a server with a client certificate

net/base/ssl_client_auth_cache.h

Index: net/base/ssl_client_auth_cache.h
diff --git a/net/base/ssl_client_auth_cache.h b/net/base/ssl_client_auth_cache.h
index 023480b2915c562872a568df88ae798324c15d4c..1fc7b768dcdb706cfcaf007ca130f9f54ae7733d 100644
--- a/net/base/ssl_client_auth_cache.h
+++ b/net/base/ssl_client_auth_cache.h
@@ -10,10 +10,11 @@
 #include <map>
 
 #include "base/ref_counted.h"
-#include "net/base/x509_certificate.h"
 
 namespace net {
 
+class X509Certificate;
+
 // The SSLClientAuthCache class is a simple cache structure to store SSL
 // client certificates. Provides lookup, insertion, and deletion of entries.
 // The parameter for doing lookups, insertions, and deletions is the server's
@@ -26,9 +27,13 @@ class SSLClientAuthCache {
   SSLClientAuthCache();
   ~SSLClientAuthCache();
 
-  // Check if we have a client certificate for SSL server at |server|.
-  // Returns the client certificate (if found) or NULL (if not found).
-  X509Certificate* Lookup(const std::string& server);
+  // Check if we have a client certificate preference for SSL server at
+  // |server|. Returns true if a preference is found.
+  // If found, |*certificate| will point to the client certificate
+  // if the user has selected a certificate, or NULL if the user has opted to
+  // not provide a certificate.
+  // If a certificate preference is not found, |*certificate| will be NULL.

[wtc, 2010/11/18 01:33:07]

This should say:
  If a certificate preference is not found, returns false.
It is best to leave |*certificate| unchanged when the function
fails.

+  bool Lookup(const std::string& server, X509Certificate** certificate);

[wtc, 2010/11/18 01:33:07]

Declare the output argument as
  scoped_refptr<X509Certificate>* certificate
to force the caller to store the returned X509Certificate
pointer in a scoped_refptr for proper reference counting.

Please update the comment block above accordingly when it
talks about |*certificate|.  (Perhaps the current text also
works for scoped_refptr.)

 
   // Add a client certificate for |server| to the cache. If there is already
   // a client certificate for |server|, it will be overwritten. Both parameters