*wip* NSS: handle chromeos system slot.

net/cert/nss_cert_database_chromeos.h

Index: net/cert/nss_cert_database_chromeos.h
diff --git a/net/cert/nss_cert_database_chromeos.h b/net/cert/nss_cert_database_chromeos.h
index 07a1e67f31afa4cc50cbd40f28d432444fd0df30..d95bb3ba6494c8ce4ad82a6cfab8806eae8e50f9 100644
--- a/net/cert/nss_cert_database_chromeos.h
+++ b/net/cert/nss_cert_database_chromeos.h
@@ -16,8 +16,12 @@ namespace net {
 
 class NET_EXPORT NSSCertDatabaseChromeOS : public NSSCertDatabase {
  public:
+  // |public_slot| is the NSS software slot for the user.
+  // |private_slot| is the TPM slot for the user (if a TPM is present).
+  // |system_slot| is the system TPM slot (if system TPM slot is enabled).
   NSSCertDatabaseChromeOS(crypto::ScopedPK11Slot public_slot,
-                          crypto::ScopedPK11Slot private_slot);
+                          crypto::ScopedPK11Slot private_slot,
+                          crypto::ScopedPK11Slot system_slot);
   virtual ~NSSCertDatabaseChromeOS();
 
   // NSSCertDatabase implementation.