Created by: wangkuiyi

Our CMakeLists file contains

proto_library(op_desc SRCS op_desc.proto DEPS attribute_proto)
cc_test(op_proto_test SRCS op_proto_test.cc DEPS op_proto protobuf)
cc_test(op_desc_test SRCS op_desc_test.cc DEPS op_desc protobuf)

cc_library(attribute SRCS attribute.cc DEPS op_desc op_proto)

cc_library(operator SRCS operator.cc DEPS op_desc device_context tensor scope attribute)
cc_test(operator_test SRCS operator_test.cc DEPS operator op_registry)

cc_library(grad_op_builder SRCS grad_op_builder.cc DEPS op_proto operator)
cc_library(op_registry SRCS op_registry.cc DEPS op_desc grad_op_builder)
cc_test(op_registry_test SRCS op_registry_test.cc DEPS op_registry)
cc_test(grad_op_builder_test SRCS grad_op_builder_test.cc DEPS grad_op_builder op_registry add_op)

py_proto_compile(framework_py_proto SRCS attribute.proto op_proto.proto op_desc.proto)

We can see that operator depends on op_desc and attribute, and the latter depends on op_proto as well. As this dependency propagates in following rules, any target that depends on op_desc also depends on op_desc. So we can merged these two proto files together.