[ONOS] PCEP provider changes, added node listeners to topology provider

Change-Id: I98bc6445ee78a8f0bf53f897f0a25f678ec7fc99
diff --git a/protocols/pcep/api/src/main/java/org/onosproject/pcep/controller/PcepClient.java b/protocols/pcep/api/src/main/java/org/onosproject/pcep/controller/PcepClient.java
index afeeae8..6ab804c 100644
--- a/protocols/pcep/api/src/main/java/org/onosproject/pcep/controller/PcepClient.java
+++ b/protocols/pcep/api/src/main/java/org/onosproject/pcep/controller/PcepClient.java
@@ -135,4 +135,18 @@
      * @return capability supported by client
      */
     ClientCapability capability();
+
+    /**
+     * Adds PCEP device when session is successfully established.
+     *
+     * @param pc PCEP client details
+     */
+    void addNode(PcepClient pc);
+
+    /**
+     * Removes PCEP device when session is disconnected.
+     *
+     * @param pccId PCEP client ID
+     */
+    void deleteNode(PccId pccId);
 }