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

components/sync/driver/fake_generic_change_processor.cc

Index: components/sync/driver/fake_generic_change_processor.cc
diff --git a/components/sync/driver/fake_generic_change_processor.cc b/components/sync/driver/fake_generic_change_processor.cc
index 496fc517860490a491b987165d45a262f87d654b..358b141677b5a9c17a2f5955495b5f65364a9256 100644
--- a/components/sync/driver/fake_generic_change_processor.cc
+++ b/components/sync/driver/fake_generic_change_processor.cc
@@ -15,10 +15,10 @@ namespace syncer {
 FakeGenericChangeProcessor::FakeGenericChangeProcessor(ModelType type,
                                                        SyncClient* sync_client)
     : GenericChangeProcessor(type,
-                             NULL,
+                             nullptr,
                              base::WeakPtr<SyncableService>(),
                              base::WeakPtr<SyncMergeResult>(),
-                             NULL,
+                             nullptr,
                              sync_client,
                              nullptr),
       sync_model_has_user_created_nodes_(true),