Remove the deprecated NSSCertDatabase::GetInstance() .

chrome/browser/net/nss_context.h

Index: chrome/browser/net/nss_context.h
diff --git a/chrome/browser/net/nss_context.h b/chrome/browser/net/nss_context.h
index feb178ca7c8a1de8e17a6fbb905f18d4603ff56b..33023c0012cd92621a56c4f78dc9401ee0b78646 100644
--- a/chrome/browser/net/nss_context.h
+++ b/chrome/browser/net/nss_context.h
@@ -40,7 +40,7 @@ crypto::ScopedPK11Slot GetPrivateNSSKeySlotForResourceContext(
 // |callback| will be run once the DB is initialized. Ownership is not
 // transferred, but the caller may save the pointer, which will remain valid for
 // the lifetime of the ResourceContext.
-// Should be called only on the IO thread.
+// Must be called only on the IO thread.
 net::NSSCertDatabase* GetNSSCertDatabaseForResourceContext(
     content::ResourceContext* context,
     const base::Callback<void(net::NSSCertDatabase*)>& callback)