Use TaskScheduler instead of WorkerPool in nss_cert_database.cc.

net/cert/nss_cert_database.h

Index: net/cert/nss_cert_database.h
diff --git a/net/cert/nss_cert_database.h b/net/cert/nss_cert_database.h
index 2ee859dbb71603bd2d36b94d41ed6eaf88212c53..b5e971f1ad17025ee72642fda7e4dc734c64f117 100644
--- a/net/cert/nss_cert_database.h
+++ b/net/cert/nss_cert_database.h
@@ -25,7 +25,6 @@
 namespace base {
 template <class ObserverType>
 class ObserverListThreadSafe;
-class TaskRunner;
 }
 
 namespace net {
@@ -249,10 +248,6 @@ class NET_EXPORT NSSCertDatabase {
   // Check whether cert is stored in a hardware slot.
   bool IsHardwareBacked(const X509Certificate* cert) const;
 
-  // Overrides task runner that's used for running slow tasks.
-  void SetSlowTaskRunnerForTest(
-      const scoped_refptr<base::TaskRunner>& task_runner);
-
  protected:
   // Certificate listing implementation used by |ListCerts*| and
   // |ListCertsSync|. Static so it may safely be used on the worker thread.
@@ -261,11 +256,6 @@ class NET_EXPORT NSSCertDatabase {
   static void ListCertsImpl(crypto::ScopedPK11Slot slot,
                             CertificateList* certs);
 
-  // Gets task runner that should be used for slow tasks like certificate
-  // listing. Defaults to a base::WorkerPool runner, but may be overriden
-  // in tests (see SetSlowTaskRunnerForTest).
-  scoped_refptr<base::TaskRunner> GetSlowTaskRunner() const;
-
  protected:
   // Broadcasts notifications to all registered observers.
   void NotifyObserversCertDBChanged(const X509Certificate* cert);
@@ -299,9 +289,6 @@ class NET_EXPORT NSSCertDatabase {
   // A helper observer that forwards events from this database to CertDatabase.
   std::unique_ptr<Observer> cert_notification_forwarder_;
 
-  // Task runner that should be used in tests if set.
-  scoped_refptr<base::TaskRunner> slow_task_runner_for_test_;
-
   const scoped_refptr<base::ObserverListThreadSafe<Observer>> observer_list_;
 
   base::WeakPtrFactory<NSSCertDatabase> weak_factory_;