Revert 66719 - Reland r65996. Disallows Singletons on non-joinable thread....

net/base/ev_root_ca_metadata.cc

Index: net/base/ev_root_ca_metadata.cc
===================================================================
--- net/base/ev_root_ca_metadata.cc	(revision 66790)
+++ net/base/ev_root_ca_metadata.cc	(working copy)
@@ -13,8 +13,8 @@
 #include <stdlib.h>
 #endif
 
-#include "base/lazy_instance.h"
 #include "base/logging.h"
+#include "base/singleton.h"
 
 namespace net {
 
@@ -283,13 +283,9 @@
 };
 #endif
 
-static base::LazyInstance<EVRootCAMetadata,
-                          base::LeakyLazyInstanceTraits<EVRootCAMetadata> >
-    g_ev_root_ca_metadata(base::LINKER_INITIALIZED);
-
 // static
 EVRootCAMetadata* EVRootCAMetadata::GetInstance() {
-  return g_ev_root_ca_metadata.Pointer();
+  return Singleton<EVRootCAMetadata>::get();
 }
 
 bool EVRootCAMetadata::GetPolicyOID(