Decoupling PortStatistcsDiscovery and DeviceDescriptionDiscovery

Change-Id: Iea4b06cf4d8caf4048180cd9c4fa975f31efe5ea
diff --git a/core/api/src/main/java/org/onosproject/net/device/PortStatisticsDiscovery.java b/core/api/src/main/java/org/onosproject/net/device/PortStatisticsDiscovery.java
index 86238f6..fb34ff6 100644
--- a/core/api/src/main/java/org/onosproject/net/device/PortStatisticsDiscovery.java
+++ b/core/api/src/main/java/org/onosproject/net/device/PortStatisticsDiscovery.java
@@ -16,12 +16,14 @@
 
 package org.onosproject.net.device;
 
+import org.onosproject.net.driver.HandlerBehaviour;
+
 import java.util.Collection;
 
 /**
  * Handler behaviour capable of collecting and updating port statistics.
  */
-public interface PortStatisticsDiscovery extends DeviceDescriptionDiscovery {
+public interface PortStatisticsDiscovery extends HandlerBehaviour {
 
     /**
      * Returns a list of port statistics descriptions appropriately annotated
diff --git a/drivers/huawei/src/main/java/org/onosproject/drivers/huawei/HuaweiDeviceDescription.java b/drivers/huawei/src/main/java/org/onosproject/drivers/huawei/HuaweiDeviceDescription.java
index 7c0a478..0b66710 100644
--- a/drivers/huawei/src/main/java/org/onosproject/drivers/huawei/HuaweiDeviceDescription.java
+++ b/drivers/huawei/src/main/java/org/onosproject/drivers/huawei/HuaweiDeviceDescription.java
@@ -22,6 +22,7 @@
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.device.DefaultDeviceDescription;
 import org.onosproject.net.device.DeviceDescription;
+import org.onosproject.net.device.DeviceDescriptionDiscovery;
 import org.onosproject.net.device.DeviceService;
 import org.onosproject.net.device.PortDescription;
 import org.onosproject.net.device.PortStatistics;
@@ -56,7 +57,7 @@
  * routers.
  */
 public class HuaweiDeviceDescription extends AbstractHandlerBehaviour
-        implements PortStatisticsDiscovery {
+        implements PortStatisticsDiscovery, DeviceDescriptionDiscovery {
 
     private final Logger log = getLogger(getClass());