[Sync] Replacing NULL with nullptr/null throughout sync code.

components/sync_bookmarks/bookmark_change_processor.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_BOOKMARKS_BOOKMARK_CHANGE_PROCESSOR_H_
 #define COMPONENTS_SYNC_BOOKMARKS_BOOKMARK_CHANGE_PROCESSOR_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 225 matching lines @@
                                 BookmarkModelAssociator* associator);
 
   // Creates or updates a sync node associated with |node|.
   void CreateOrUpdateSyncNode(const bookmarks::BookmarkNode* node);
 
   // Returns false if |node| should not be synced.
   bool CanSyncNode(const bookmarks::BookmarkNode* node);
 
   base::ThreadChecker thread_checker_;
 
-  // The bookmark model we are processing changes from.  Non-NULL when
+  // The bookmark model we are processing changes from.  Non-null when
   // |running_| is true.
   bookmarks::BookmarkModel* bookmark_model_;
 
   syncer::SyncClient* sync_client_;
 
   // The two models should be associated according to this ModelAssociator.
   BookmarkModelAssociator* model_associator_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkChangeProcessor);
 };
 
 }  // namespace sync_bookmarks
 
 #endif  // COMPONENTS_SYNC_BOOKMARKS_BOOKMARK_CHANGE_PROCESSOR_H_