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

net/cert/nss_cert_database_unittest.cc

Index: net/cert/nss_cert_database_unittest.cc
diff --git a/net/cert/nss_cert_database_unittest.cc b/net/cert/nss_cert_database_unittest.cc
index 0d99c8ac3e22db5d11b1c1cffaf62d23ae41fe94..235ea44cc0d479be12c91ca4379e628a07e0618b 100644
--- a/net/cert/nss_cert_database_unittest.cc
+++ b/net/cert/nss_cert_database_unittest.cc
@@ -15,12 +15,10 @@
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
-#include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/test/scoped_task_scheduler.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "crypto/scoped_nss_types.h"
 #include "crypto/scoped_test_nss_db.h"
@@ -63,9 +61,6 @@ void SwapCertList(CertificateList* destination,
 
 class CertDatabaseNSSTest : public testing::Test {
  public:
-  CertDatabaseNSSTest()
-      : scoped_task_scheduler_(base::MessageLoop::current()) {}
-
   void SetUp() override {
     ASSERT_TRUE(test_nssdb_.is_open());
     cert_db_.reset(new NSSCertDatabase(
@@ -130,7 +125,6 @@ class CertDatabaseNSSTest : public testing::Test {
     return result;
   }
 
-  base::test::ScopedTaskScheduler scoped_task_scheduler_;
   std::unique_ptr<NSSCertDatabase> cert_db_;
   const CertificateList empty_cert_list_;
   crypto::ScopedTestNSSDB test_nssdb_;
@@ -151,6 +145,7 @@ TEST_F(CertDatabaseNSSTest, ListCerts) {
   // This test isn't terribly useful, though it will at least let valgrind test
   // for leaks.
   CertificateList certs;
+  cert_db_->SetSlowTaskRunnerForTest(base::ThreadTaskRunnerHandle::Get());
   cert_db_->ListCerts(base::Bind(&SwapCertList, base::Unretained(&certs)));
   EXPECT_EQ(0U, certs.size());