ONOS-745 Refactoring topology to compute only broadcast tree and not pre-compute paths.
ONOS-744 Refactoring graph search to allow requesting max number of paths.

Change-Id: I28467246b92df32ebb3155c45774ecc051fdd3dd
diff --git a/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyCluster.java b/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyCluster.java
index 9eadec1..aaf170f 100644
--- a/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyCluster.java
+++ b/core/api/src/main/java/org/onosproject/net/topology/DefaultTopologyCluster.java
@@ -15,8 +15,6 @@
  */
 package org.onosproject.net.topology;
 
-import org.onosproject.net.DeviceId;
-
 import java.util.Objects;
 
 import static com.google.common.base.MoreObjects.toStringHelper;
@@ -29,7 +27,7 @@
     private final ClusterId id;
     private final int deviceCount;
     private final int linkCount;
-    private final DeviceId root;
+    private final TopologyVertex root;
 
     /**
      * Creates a new topology cluster descriptor with the specified attributes.
@@ -40,7 +38,7 @@
      * @param root        cluster root node
      */
     public DefaultTopologyCluster(ClusterId id, int deviceCount, int linkCount,
-                                  DeviceId root) {
+                                  TopologyVertex root) {
         this.id = id;
         this.deviceCount = deviceCount;
         this.linkCount = linkCount;
@@ -63,7 +61,7 @@
     }
 
     @Override
-    public DeviceId root() {
+    public TopologyVertex root() {
         return root;
     }