Removing cyclic dependency (pytorch#20511)

Summary:
Pull Request resolved: pytorch#20511

Removed cyclic dependency of caffe2/core/net.h and workspace.h

Differential Revision: D15303412

fbshipit-source-id: 6e772e372cd0cf2af05d7815f1df8ae20bc2a65e

Author: Kedar Pujara

caffe2/core/net.h

@@ -17,7 +17,6 @@
 #include "caffe2/core/observer.h"
 #include "caffe2/core/operator_schema.h"
 #include "caffe2/core/tensor.h"
-#include "caffe2/core/workspace.h"
 #include "caffe2/proto/caffe2_pb.h"
 #include "caffe2/utils/simple_queue.h"
 

caffe2/predictor/predictor.cc

@@ -4,6 +4,7 @@
 
 namespace caffe2 {
 
+class Workspace;
 namespace {
 
 void enforceIsTensor(Workspace* ws, const std::string& name) {

caffe2/predictor/predictor_config.h

@@ -1,7 +1,8 @@
 #pragma once
 #include <memory>
-#include "caffe2/core/net.h"
+
 #include "caffe2/core/tensor.h"
+#include "caffe2/core/workspace.h"
 #include "caffe2/proto/metanet.pb.h"
 #include "caffe2/proto/predictor_consts.pb.h"