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

components/sync/driver/generic_change_processor.h

 // Copyright 2014 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_DRIVER_GENERIC_CHANGE_PROCESSOR_H_
 #define COMPONENTS_SYNC_DRIVER_GENERIC_CHANGE_PROCESSOR_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 34 matching lines @@
 // which then get converted into SyncChange's and sent to the local service.
 //
 // As a rule, the GenericChangeProcessor is not thread safe, and should only
 // be used on the same thread in which it was created.
 class GenericChangeProcessor : public ChangeProcessor,
                                public SyncChangeProcessor,
                                public AttachmentService::Delegate,
                                public base::NonThreadSafe {
  public:
   // Create a change processor for |type| and connect it to the syncer.
-  // |attachment_store| can be NULL which means that datatype will not use sync
+  // |attachment_store| can be null which means that datatype will not use sync
   // attachments.
   GenericChangeProcessor(
       ModelType type,
       std::unique_ptr<DataTypeErrorHandler> error_handler,
       const base::WeakPtr<SyncableService>& local_service,
       const base::WeakPtr<SyncMergeResult>& merge_result,
       UserShare* user_share,
       SyncClient* sync_client,
       std::unique_ptr<AttachmentStoreForSync> attachment_store);
   ~GenericChangeProcessor() override;
@@ skipping 99 matching lines @@
   // Set in ApplyChangesFromSyncModel, consumed in CommitChangesFromSyncModel.
   SyncChangeList syncer_changes_;
 
   // Our handle to the sync model. Unlike normal ChangeProcessors, we need to
   // be able to access the sync model before the change processor begins
   // listening to changes (the local_service_ will be interacting with us
   // when it starts up). As such we can't wait until Start(_) has been called,
   // and have to keep a local pointer to the user_share.
   UserShare* const share_handle_;
 
-  // AttachmentService for datatype. Can be NULL if datatype doesn't use
+  // AttachmentService for datatype. Can be null if datatype doesn't use
   // attachments.
   std::unique_ptr<AttachmentService> attachment_service_;
 
   // List of observers that want to be notified of local changes being written.
   base::ObserverList<LocalChangeObserver> local_change_observers_;
 
   // Must be destroyed before attachment_service_ to ensure WeakPtrs are
   // invalidated before attachment_service_ is destroyed.
-  // Can be NULL if attachment_service_ is NULL;
+  // Can be null if attachment_service_ is null;
   std::unique_ptr<base::WeakPtrFactory<AttachmentService>>
       attachment_service_weak_ptr_factory_;
   AttachmentServiceProxy attachment_service_proxy_;
   base::WeakPtrFactory<GenericChangeProcessor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GenericChangeProcessor);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_GENERIC_CHANGE_PROCESSOR_H_