Fix compile error

Replace `OperatorPtr` with `std::shared_ptr<OperatorBase>`

paddle/framework/grad_op_creator_test.cc

@@ -9,8 +9,9 @@ namespace paddle {
 namespace framework {
 
 TEST(GradOpCreator, AddTwo) {
-  OperatorPtr add_op(OpRegistry::CreateOp("add_two", {"x", "y"}, {"out"}, {}));
-  OperatorPtr grad_add_op = OpRegistry::CreateGradOp(add_op);
+  std::shared_ptr<OperatorBase> add_op(
+      OpRegistry::CreateOp("add_two", {"x", "y"}, {"out"}, {}));
+  std::shared_ptr<OperatorBase> grad_add_op = OpRegistry::CreateGradOp(add_op);
   EXPECT_EQ(static_cast<int>(grad_add_op->inputs_.size()), 4);
   EXPECT_EQ(static_cast<int>(grad_add_op->outputs_.size()), 2);
   EXPECT_EQ(grad_add_op->Input("X"), "x");

paddle/framework/op_registry.h

@@ -298,9 +298,10 @@ class OpRegistry {
     return CreateOp(op_desc.type(), inputs, outputs, attrs);
   }
 
-  static OperatorPtr CreateGradOp(OperatorPtr op) {
+  static std::shared_ptr<OperatorBase> CreateGradOp(
+      std::shared_ptr<OperatorBase> op) {
     GradOpCreator creator(op.get());
-    OperatorPtr grad_op(creator.Create());
+    std::shared_ptr<OperatorBase> grad_op(creator.Create());
     grad_op->Init();
     return grad_op;
   }