xds: CdsLoadBalancer2 to use acceptResolvedAddresses (#9570)

xds: CdsLoadBalancer2 to use acceptResolvedAddresses

Moving over from handleResolvedAddresses() as part of an API migration.
diff --git a/xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java b/xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java
index afbb210..0db0f59 100644
--- a/xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java
+++ b/xds/src/main/java/io/grpc/xds/CdsLoadBalancer2.java
@@ -79,9 +79,9 @@
   }
 
   @Override
-  public void handleResolvedAddresses(ResolvedAddresses resolvedAddresses) {
+  public boolean acceptResolvedAddresses(ResolvedAddresses resolvedAddresses) {
     if (this.resolvedAddresses != null) {
-      return;
+      return true;
     }
     logger.log(XdsLogLevel.DEBUG, "Received resolution result: {0}", resolvedAddresses);
     this.resolvedAddresses = resolvedAddresses;
@@ -91,6 +91,7 @@
     logger.log(XdsLogLevel.INFO, "Config: {0}", config);
     cdsLbState = new CdsLbState(config.name);
     cdsLbState.start();
+    return true;
   }
 
   @Override
diff --git a/xds/src/test/java/io/grpc/xds/CdsLoadBalancer2Test.java b/xds/src/test/java/io/grpc/xds/CdsLoadBalancer2Test.java
index 23c3c4d..60ddb9f 100644
--- a/xds/src/test/java/io/grpc/xds/CdsLoadBalancer2Test.java
+++ b/xds/src/test/java/io/grpc/xds/CdsLoadBalancer2Test.java
@@ -135,7 +135,7 @@
     lbRegistry.register(new FakeLoadBalancerProvider("least_request_experimental",
         new LeastRequestLoadBalancerProvider()));
     loadBalancer = new CdsLoadBalancer2(helper, lbRegistry);
-    loadBalancer.handleResolvedAddresses(
+    loadBalancer.acceptResolvedAddresses(
         ResolvedAddresses.newBuilder()
             .setAddresses(Collections.<EquivalentAddressGroup>emptyList())
             .setAttributes(