Transform a tensor into itself (identity) if possible.
tf.contrib.graph_editor.keep_t_if_possible_handler( info, t )
This handler transform a tensor into itself if the source and destination graph are the same. Otherwise it will create a placeholder. This handler is typically used to transform a hidden input tensors.
info: Transform._TmpInfo instance.
t: tensor whose input must be transformed into a place holder.
The tensor generated by the newly created place holder.