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

components/sync/engine_impl/test_entry_factory.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_ENGINE_IMPL_TEST_ENTRY_FACTORY_H_
 #define COMPONENTS_SYNC_ENGINE_IMPL_TEST_ENTRY_FACTORY_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 27 matching lines @@
 
   // Create a new unapplied update without a parent.
   int64_t CreateUnappliedNewItem(const std::string& item_id,
                                  const sync_pb::EntitySpecifics& specifics,
                                  bool is_unique);
 
   // Create an unsynced unique_client_tag item in the database.  If item_id is a
   // local ID, it will be treated as a create-new.  Otherwise, if it's a server
   // ID, we'll fake the server data so that it looks like it exists on the
   // server.  Returns the methandle of the created item in |metahandle_out| if
-  // not NULL.
+  // not null.
   void CreateUnsyncedItem(const syncable::Id& item_id,
                           const syncable::Id& parent_id,
                           const std::string& name,
                           bool is_folder,
                           ModelType model_type,
                           int64_t* metahandle_out);
 
   // Creates a bookmark that is both unsynced an an unapplied update.  Returns
   // the metahandle of the created item.
   int64_t CreateUnappliedAndUnsyncedBookmarkItem(const std::string& name);
@@ skipping 68 matching lines @@
  private:
   syncable::Directory* directory_;
   int64_t next_revision_;
 
   DISALLOW_COPY_AND_ASSIGN(TestEntryFactory);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_TEST_ENTRY_FACTORY_H_