Destroy all Singletons and LazyInstances between each test.

chromeos/network/onc/onc_certificate_importer_unittest.cc

Index: chromeos/network/onc/onc_certificate_importer_unittest.cc
diff --git a/chromeos/network/onc/onc_certificate_importer_unittest.cc b/chromeos/network/onc/onc_certificate_importer_unittest.cc
index 7b5d18e5eac0072d3cc07c90e32c5a55c1820f05..f632840c365125a27154e2ff91344593a460239e 100644
--- a/chromeos/network/onc/onc_certificate_importer_unittest.cc
+++ b/chromeos/network/onc/onc_certificate_importer_unittest.cc
@@ -12,6 +12,7 @@
 
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/threading/platform_thread.h"
 #include "base/values.h"
 #include "chromeos/network/onc/onc_constants.h"
 #include "chromeos/network/onc/onc_test_utils.h"
@@ -80,6 +81,10 @@ class ONCCertificateImporterTest : public testing::Test {
   void AddCertificatesFromFile(
       std::string filename,
       CertificateImporter::ParseResult expected_parse_result) {
+    // This 1 second sleep is necessary because NSS has a caching bug. This
+    // can be removed once http://crbug.com/238654 is fixed.
+    base::PlatformThread::Sleep(base::TimeDelta::FromSeconds(1));
+
     scoped_ptr<base::DictionaryValue> onc =
         test_utils::ReadTestDictionary(filename);
     base::Value* certificates_value = NULL;