Collect the stripped OpDefs for ops used by a graph.
This function computes the
stripped_op_list field of
similar protos. The result can be communicated from the producer to the
consumer, which can then use the C++ function
RemoveNewDefaultAttrsFromGraphDef to improve forwards compatibility.
GraphDefproto, as from
OpList of ops used by the graph.
ValueError: If an unregistered op is used.