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

components/sync/test/engine/mock_connection_manager.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.
 //
 // Mock ServerConnectionManager class for use in client unit tests.
 
 #ifndef COMPONENTS_SYNC_TEST_ENGINE_MOCK_CONNECTION_MANAGER_H_
 #define COMPONENTS_SYNC_TEST_ENGINE_MOCK_CONNECTION_MANAGER_H_
 
 #include <stdint.h>
@@ skipping 337 matching lines @@
   base::Lock store_birthday_lock_;
   bool store_birthday_sent_;
   bool client_stuck_;
   std::string commit_time_rename_prepended_string_;
 
   // On each PostBufferToPath() call, we decrement this counter.  The call fails
   // iff we hit zero at that call.
   int countdown_to_postbuffer_fail_;
 
   // Our directory.  Used only to ensure that we are not holding the transaction
-  // lock when performing network I/O.  Can be NULL if the test author is
+  // lock when performing network I/O.  Can be null if the test author is
   // confident this can't happen.
   syncable::Directory* directory_;
 
   // The updates we'll return to the next request.
   std::list<sync_pb::GetUpdatesResponse> update_queue_;
   base::Closure mid_commit_callback_;
   MidCommitObserver* mid_commit_observer_;
 
   // The keystore key we return for a GetUpdates with need_encryption_key set.
   std::string keystore_key_;
@@ skipping 37 matching lines @@
   std::string next_token_;
 
   std::vector<sync_pb::ClientToServerMessage> requests_;
 
   DISALLOW_COPY_AND_ASSIGN(MockConnectionManager);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_TEST_ENGINE_MOCK_CONNECTION_MANAGER_H_