[Sync] Replacing NULL with nullptr in code and null in comments for components/sync/

components/sync/engine/engine_util.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/sync/engine/engine_util.h"
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/sync/base/cryptographer.h"
 #include "components/sync/protocol/attachments.pb.h"
 #include "components/sync/protocol/password_specifics.pb.h"
 #include "components/sync/protocol/sync.pb.h"
 
 namespace syncer {
 
 namespace {
 
 bool EndsWithSpace(const std::string& string) {
   return !string.empty() && *string.rbegin() == ' ';
 }
 }
 
 sync_pb::PasswordSpecificsData* DecryptPasswordSpecifics(
     const sync_pb::EntitySpecifics& specifics,
     Cryptographer* crypto) {
   if (!specifics.has_password())
-    return NULL;
+    return nullptr;
   const sync_pb::PasswordSpecifics& password_specifics = specifics.password();
   if (!password_specifics.has_encrypted())
-    return NULL;
+    return nullptr;
   const sync_pb::EncryptedData& encrypted = password_specifics.encrypted();
   std::unique_ptr<sync_pb::PasswordSpecificsData> data(
       new sync_pb::PasswordSpecificsData);
   if (!crypto->CanDecrypt(encrypted))
-    return NULL;
+    return nullptr;
   if (!crypto->Decrypt(encrypted, data.get()))
-    return NULL;
+    return nullptr;
   return data.release();
 }
 
 // The list of names which are reserved for use by the server.
 static const char* kForbiddenServerNames[] = {"", ".", ".."};
 
 // When taking a name from the syncapi, append a space if it matches the
 // pattern of a server-illegal name followed by zero or more spaces.
 void SyncAPINameToServerName(const std::string& syncer_name, std::string* out) {
   *out = syncer_name;
@@ skipping 60 matching lines @@
 
 bool AreAttachmentMetadataEqual(const sync_pb::AttachmentMetadata& left,
                                 const sync_pb::AttachmentMetadata& right) {
   if (left.SerializeAsString() == right.SerializeAsString()) {
     return true;
   }
   return false;
 }
 
 }  // namespace syncer