Make NSSCertDatabase::ListCerts work async on a worker thread.

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 63eab07542339582a998b2569c1109a6bcc8c70a..0faf185f9af90a8208deb9e7d5395d3e6e3a14e4 100644
--- a/net/cert/nss_cert_database_chromeos.h
+++ b/net/cert/nss_cert_database_chromeos.h
@@ -6,7 +6,9 @@
 #define NET_CERT_NSS_CERT_DATABASE_CHROMEOS_
 
 #include "base/callback.h"
+#include "base/memory/ref_counted.h"
 #include "crypto/scoped_nss_types.h"
+#include "net/base/net_export.h"
 #include "net/cert/nss_cert_database.h"
 #include "net/cert/nss_profile_filter_chromeos.h"
 
@@ -19,10 +21,11 @@ class NET_EXPORT NSSCertDatabaseChromeOS : public NSSCertDatabase {
   virtual ~NSSCertDatabaseChromeOS();
 
   // NSSCertDatabase implementation.
-  virtual void ListCerts(CertificateList* certs) OVERRIDE;
+  virtual void ListCertsSync(CertificateList* certs) OVERRIDE;
+  virtual scoped_refptr<NSSDatabaseFilter> GetDatabaseFilter() const OVERRIDE;
   virtual crypto::ScopedPK11Slot GetPublicSlot() const OVERRIDE;
   virtual crypto::ScopedPK11Slot GetPrivateSlot() const OVERRIDE;
-  virtual void ListModules(CryptoModuleList* modules, bool need_rw) const
+  virtual void ListModulesSync(CryptoModuleList* modules, bool need_rw) const
       OVERRIDE;
 
   // TODO(mattm): handle trust setting, deletion, etc correctly when certs exist
@@ -32,7 +35,7 @@ class NET_EXPORT NSSCertDatabaseChromeOS : public NSSCertDatabase {
  private:
   crypto::ScopedPK11Slot public_slot_;
   crypto::ScopedPK11Slot private_slot_;
-  NSSProfileFilterChromeOS profile_filter_;
+  scoped_refptr<NSSProfileFilterChromeOS> profile_filter_;
 
   DISALLOW_COPY_AND_ASSIGN(NSSCertDatabaseChromeOS);
 };