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

chromeos/cert_loader.h

Index: chromeos/cert_loader.h
diff --git a/chromeos/cert_loader.h b/chromeos/cert_loader.h
index 94f6a4114fb67ddc0dd7d83743df76ffb81088db..848a2c8ec8376e5e4d64e23a21f9eefb3ddd5533 100644
--- a/chromeos/cert_loader.h
+++ b/chromeos/cert_loader.h
@@ -17,10 +17,6 @@
 #include "chromeos/chromeos_export.h"
 #include "net/cert/cert_database.h"
 
-namespace base {
-class TaskRunner;
-}
-
 namespace net {
 class NSSCertDatabase;
 class X509Certificate;
@@ -64,14 +60,12 @@ class CHROMEOS_EXPORT CertLoader : public net::CertDatabase::Observer {
   static std::string GetPkcs11IdForCert(const net::X509Certificate& cert);
 
   // Starts the CertLoader with the NSS cert database.
-  // The CertLoader will _not_ take the ownership of the database.
+  // The CertLoader will _not_ take the ownership of the database, but it
+  // expects it to stay alive at least until the shutdown starts on the main
+  // thread. This assumes that |StartWithNSSDB| and other methods directly
+  // using |database_| are not called during shutdown.
   void StartWithNSSDB(net::NSSCertDatabase* database);
 
-  // Sets the task runner that any slow calls will be made from, e.g. calls
-  // to the NSS database. If not set, uses base::WorkerPool.
-  void SetSlowTaskRunnerForTest(
-      const scoped_refptr<base::TaskRunner>& task_runner);
-
   void AddObserver(CertLoader::Observer* observer);
   void RemoveObserver(CertLoader::Observer* observer);
 
@@ -89,7 +83,7 @@ class CHROMEOS_EXPORT CertLoader : public net::CertDatabase::Observer {
   bool certificates_loaded() const { return certificates_loaded_; }
 
   // This will be empty until certificates_loaded() is true.
-  const net::CertificateList& cert_list() const { return cert_list_; }
+  const net::CertificateList& cert_list() const { return *cert_list_; }
 
   void force_hardware_backed_for_test() {
     force_hardware_backed_for_test_ = true;
@@ -104,7 +98,7 @@ class CHROMEOS_EXPORT CertLoader : public net::CertDatabase::Observer {
   void LoadCertificates();
 
   // Called if a certificate load task is finished.
-  void UpdateCertificates(net::CertificateList* cert_list);
+  void UpdateCertificates(scoped_ptr<net::CertificateList> cert_list);
 
   void NotifyCertificatesLoaded(bool initial_load);
 
@@ -128,14 +122,10 @@ class CHROMEOS_EXPORT CertLoader : public net::CertDatabase::Observer {
   bool force_hardware_backed_for_test_;
 
   // Cached Certificates loaded from the database.
-  net::CertificateList cert_list_;
+  scoped_ptr<net::CertificateList> cert_list_;
 
   base::ThreadChecker thread_checker_;
 
-  // TaskRunner that, if set, replaces base::WorkerPool. Should only be set in
-  // tests.
-  scoped_refptr<base::TaskRunner> slow_task_runner_for_test_;
-
   base::WeakPtrFactory<CertLoader> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CertLoader);