[Sync] The cryptographer should be able to handle empty or old nigori nodes.

chrome/browser/sync/util/cryptographer.cc

Index: chrome/browser/sync/util/cryptographer.cc
diff --git a/chrome/browser/sync/util/cryptographer.cc b/chrome/browser/sync/util/cryptographer.cc
index 4990d8b9f275f353de6ba7ef9e92263eada4ea19..dde6fb7d3543e8598bc56f1ef4d83d0a8b40efa9 100644
--- a/chrome/browser/sync/util/cryptographer.cc
+++ b/chrome/browser/sync/util/cryptographer.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <algorithm>
+
 #include "base/base64.h"
 #include "chrome/browser/sync/util/cryptographer.h"
 #include "chrome/browser/password_manager/encryptor.h"
@@ -326,7 +328,7 @@ void Cryptographer::UpdateEncryptedTypesFromNigori(
     return;
   }
 
-  SetEncryptedTypes(encrypted_types);
+  MergeEncryptedTypes(encrypted_types);
 }
 
 void Cryptographer::UpdateNigoriFromEncryptedTypes(
@@ -376,14 +378,15 @@ syncable::ModelTypeSet Cryptographer::GetEncryptedTypes() const {
   return encrypted_types_;
 }
 
-void Cryptographer::SetEncryptedTypesForTest(
+void Cryptographer::MergeEncryptedTypesForTest(
     const syncable::ModelTypeSet& encrypted_types) {
-  SetEncryptedTypes(encrypted_types);
+  MergeEncryptedTypes(encrypted_types);
 }
 
-void Cryptographer::SetEncryptedTypes(
+void Cryptographer::MergeEncryptedTypes(
     const syncable::ModelTypeSet& encrypted_types) {
-  if (encrypted_types_ == encrypted_types) {
+  if (std::includes(encrypted_types_.begin(), encrypted_types_.end(),
+                    encrypted_types.begin(), encrypted_types.end())) {
     return;
   }
   encrypted_types_.insert(encrypted_types.begin(), encrypted_types.end());