Revert of Use TaskScheduler instead of WorkerPool in nss_cert_database.cc.

chromeos/network/network_connection_handler_unittest.cc

Index: chromeos/network/network_connection_handler_unittest.cc
diff --git a/chromeos/network/network_connection_handler_unittest.cc b/chromeos/network/network_connection_handler_unittest.cc
index 9ea2356d63c5c38519f7d6ff2f332a662baaf6bb..8224c02e66d071cc1747a5ced8acc0782828a505 100644
--- a/chromeos/network/network_connection_handler_unittest.cc
+++ b/chromeos/network/network_connection_handler_unittest.cc
@@ -13,9 +13,9 @@
 #include "base/files/file_util.h"
 #include "base/json/json_reader.h"
 #include "base/macros.h"
+#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
-#include "base/test/scoped_task_scheduler.h"
 #include "chromeos/cert_loader.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/shill_device_client.h"
@@ -110,6 +110,7 @@ class NetworkConnectionHandlerTest : public testing::Test {
     test_nsscertdb_.reset(new net::NSSCertDatabaseChromeOS(
         crypto::ScopedPK11Slot(PK11_ReferenceSlot(test_nssdb_.slot())),
         crypto::ScopedPK11Slot(PK11_ReferenceSlot(test_nssdb_.slot()))));
+    test_nsscertdb_->SetSlowTaskRunnerForTest(message_loop_.task_runner());
 
     CertLoader::Initialize();
     CertLoader::ForceHardwareBackedForTesting();
@@ -309,7 +310,7 @@ class NetworkConnectionHandlerTest : public testing::Test {
   ShillServiceClient::TestInterface* test_service_client_;
   crypto::ScopedTestNSSDB test_nssdb_;
   std::unique_ptr<net::NSSCertDatabaseChromeOS> test_nsscertdb_;
-  base::test::ScopedTaskScheduler scoped_task_scheduler_;
+  base::MessageLoopForUI message_loop_;
   std::string result_;
 
  private: