Mac: implement <keygen> support, including adding generated cert to the Keychain.

net/base/cert_database.h

Index: net/base/cert_database.h
diff --git a/net/base/cert_database.h b/net/base/cert_database.h
index e78c22e97feb285571913ae628298c442e46c27c..4c4e1adef007ee2317d2aba7de6efb4fe4d42455 100644
--- a/net/base/cert_database.h
+++ b/net/base/cert_database.h
@@ -20,9 +20,13 @@ class CertDatabase {
  public:
   CertDatabase();
 
-  // Extract and Store User (Client) Certificate from a data blob.
-  // Return true if successful.
-  bool AddUserCert(const char* data, int len);
+  // Check whether this is a valid user cert that we have the private key for.
+  // Returns OK or a network error code such as ERR_CERT_CONTAINS_ERRORS.
+  int CheckUserCert(X509Certificate* cert);
+
+  // Store user (client) certificate. Assumes CheckUserCert has already passed.
+  // Returns OK or a network error code such as ERR_FAILED.
+  int AddUserCert(X509Certificate* cert);
 
  private:
   void Init();