[ONOS-3499] Add the set treatments of ARP_SPA, ARP_SHA and ARP_OP.

Change-Id: I7e1927bcf26e7c25fede43aa864a1b71ae2e8b49
diff --git a/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java b/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java
index 22bff7d..40291f57 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/DefaultTrafficTreatment.java
@@ -489,6 +489,21 @@
         }
 
         @Override
+        public Builder setArpSpa(IpAddress addr) {
+            return add(Instructions.modArpSpa(addr));
+        }
+
+        @Override
+        public Builder setArpSha(MacAddress addr) {
+            return add(Instructions.modArpSha(addr));
+        }
+
+        @Override
+        public Builder setArpOp(short op) {
+            return add(Instructions.modL3ArpOp(op));
+        }
+
+        @Override
         public TrafficTreatment.Builder extension(ExtensionTreatment extension,
                                                   DeviceId deviceId) {
             return add(Instructions.extension(extension, deviceId));