util: Remove child policy config from MultiChildLB state

The child policy config should be refreshed every address update, so it
shouldn't be stored in the ChildLbState. In addition, none of the
current usages actually used what was stored in the ChildLbState in a
meaningful way (it was always null).

ResolvedAddresses was also removed from createChildLbState(), as nothing
in it should be needed for creation; it varies over time and the values
passed at creation are immutable.

util/src/main/java/io/grpc/util/MultiChildLoadBalancer.java

@@ -90,7 +90,7 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
       if (existingChildLbState != null) {
         childLbMap.put(endpoint, existingChildLbState);
       } else {
-        childLbMap.put(endpoint, createChildLbState(endpoint, null, resolvedAddresses));
+        childLbMap.put(endpoint, createChildLbState(endpoint));
       }
     }
     return childLbMap;
@@ -99,9 +99,8 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
   /**
    * Override to create an instance of a subclass.
    */
-  protected ChildLbState createChildLbState(Object key, Object policyConfig,
+  protected ChildLbState createChildLbState(Object key) {
-      ResolvedAddresses resolvedAddresses) {
+    return new ChildLbState(key, pickFirstLbProvider);
-    return new ChildLbState(key, pickFirstLbProvider, policyConfig);
   }
 
   /**
@@ -133,11 +132,9 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
    * Override this if your keys are not of type Endpoint.
    * @param key Key to identify the ChildLbState
    * @param resolvedAddresses list of addresses which include attributes
-   * @param childConfig a load balancing policy config. This field is optional.
    * @return a fully loaded ResolvedAddresses object for the specified key
    */
-  protected ResolvedAddresses getChildAddresses(Object key, ResolvedAddresses resolvedAddresses,
+  protected ResolvedAddresses getChildAddresses(Object key, ResolvedAddresses resolvedAddresses) {
-      Object childConfig) {
     Endpoint endpointKey;
     if (key instanceof EquivalentAddressGroup) {
       endpointKey = new Endpoint((EquivalentAddressGroup) key);
@@ -160,7 +157,7 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
     return resolvedAddresses.toBuilder()
         .setAddresses(Collections.singletonList(eagToUse))
         .setAttributes(Attributes.newBuilder().set(IS_PETIOLE_POLICY, true).build())
-        .setLoadBalancingPolicyConfig(childConfig)
+        .setLoadBalancingPolicyConfig(null)
         .build();
   }
 
@@ -226,10 +223,8 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
   private void updateChildrenWithResolvedAddresses(ResolvedAddresses resolvedAddresses,
                                                      Map<Object, ChildLbState> newChildren) {
     for (Map.Entry<Object, ChildLbState> entry : newChildren.entrySet()) {
-      Object childConfig = entry.getValue().getConfig();
       ChildLbState childLbState = childLbStates.get(entry.getKey());
-      ResolvedAddresses childAddresses =
+      ResolvedAddresses childAddresses = getChildAddresses(entry.getKey(), resolvedAddresses);
-          getChildAddresses(entry.getKey(), resolvedAddresses, childConfig);
       childLbState.setResolvedAddresses(childAddresses); // update child
       childLbState.lb.handleResolvedAddresses(childAddresses); // update child LB
     }
@@ -328,15 +323,13 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
   public class ChildLbState {
     private final Object key;
     private ResolvedAddresses resolvedAddresses;
-    private final Object config;
 
     private final LoadBalancer lb;
     private ConnectivityState currentState;
     private SubchannelPicker currentPicker = new FixedResultPicker(PickResult.withNoResult());
 
-    public ChildLbState(Object key, LoadBalancer.Factory policyFactory, Object childConfig) {
+    public ChildLbState(Object key, LoadBalancer.Factory policyFactory) {
       this.key = key;
-      this.config = childConfig;
       this.lb = policyFactory.newLoadBalancer(createChildHelper());
       this.currentState = CONNECTING;
     }
@@ -400,10 +393,6 @@ public abstract class MultiChildLoadBalancer extends LoadBalancer {
       resolvedAddresses = newAddresses;
     }
 
-    private Object getConfig() {
-      return config;
-    }
-
     @VisibleForTesting
     public final ResolvedAddresses getResolvedAddresses() {
       return resolvedAddresses;

util/src/main/java/io/grpc/util/RoundRobinLoadBalancer.java

@@ -96,9 +96,8 @@ final class RoundRobinLoadBalancer extends MultiChildLoadBalancer {
   }
 
   @Override
-  protected ChildLbState createChildLbState(Object key, Object policyConfig,
+  protected ChildLbState createChildLbState(Object key) {
-      ResolvedAddresses resolvedAddresses) {
+    return new ChildLbState(key, pickFirstLbProvider) {
-    return new ChildLbState(key, pickFirstLbProvider, policyConfig) {
       @Override
       protected ChildLbStateHelper createChildHelper() {
         return new ChildLbStateHelper() {

xds/src/main/java/io/grpc/xds/ClusterManagerLoadBalancer.java

@@ -70,8 +70,7 @@ class ClusterManagerLoadBalancer extends MultiChildLoadBalancer {
   }
 
   @Override
-  protected ResolvedAddresses getChildAddresses(Object key, ResolvedAddresses resolvedAddresses,
+  protected ResolvedAddresses getChildAddresses(Object key, ResolvedAddresses resolvedAddresses) {
-      Object unusedChildConfig) {
     ClusterManagerConfig config = (ClusterManagerConfig)
         resolvedAddresses.getLoadBalancingPolicyConfig();
     Object childConfig = config.childPolicies.get(key);
@@ -87,7 +86,7 @@ class ClusterManagerLoadBalancer extends MultiChildLoadBalancer {
       for (String key : config.childPolicies.keySet()) {
         ChildLbState child = getChildLbState(key);
         if (child == null) {
-          child = new ClusterManagerLbState(key, GracefulSwitchLoadBalancerFactory.INSTANCE, null);
+          child = new ClusterManagerLbState(key, GracefulSwitchLoadBalancerFactory.INSTANCE);
         }
         newChildPolicies.put(key, child);
       }
@@ -204,9 +203,8 @@ class ClusterManagerLoadBalancer extends MultiChildLoadBalancer {
     @Nullable
     ScheduledHandle deletionTimer;
 
-    public ClusterManagerLbState(Object key, LoadBalancer.Factory policyFactory,
+    public ClusterManagerLbState(Object key, LoadBalancer.Factory policyFactory) {
-        Object childConfig) {
+      super(key, policyFactory);
-      super(key, policyFactory, childConfig);
     }
 
     @Override

xds/src/main/java/io/grpc/xds/LeastRequestLoadBalancer.java

@@ -126,9 +126,8 @@ final class LeastRequestLoadBalancer extends MultiChildLoadBalancer {
   }
 
   @Override
-  protected ChildLbState createChildLbState(Object key, Object policyConfig,
+  protected ChildLbState createChildLbState(Object key) {
-      ResolvedAddresses unused) {
+    return new LeastRequestLbState(key, pickFirstLbProvider);
-    return new LeastRequestLbState(key, pickFirstLbProvider, policyConfig);
   }
 
   private void updateBalancingState(ConnectivityState state, SubchannelPicker picker) {
@@ -320,9 +319,8 @@ final class LeastRequestLoadBalancer extends MultiChildLoadBalancer {
   protected class LeastRequestLbState extends ChildLbState {
     private final AtomicInteger activeRequests = new AtomicInteger(0);
 
-    public LeastRequestLbState(Object key, LoadBalancerProvider policyProvider,
+    public LeastRequestLbState(Object key, LoadBalancerProvider policyProvider) {
-        Object childConfig) {
+      super(key, policyProvider);
-      super(key, policyProvider, childConfig);
     }
 
     int getActiveRequests() {

xds/src/main/java/io/grpc/xds/RingHashLoadBalancer.java

@@ -219,9 +219,8 @@ final class RingHashLoadBalancer extends MultiChildLoadBalancer {
   }
 
   @Override
-  protected ChildLbState createChildLbState(Object key, Object policyConfig,
+  protected ChildLbState createChildLbState(Object key) {
-      ResolvedAddresses resolvedAddresses) {
+    return new ChildLbState(key, lazyLbFactory);
-    return new ChildLbState(key, lazyLbFactory, null);
   }
 
   private Status validateAddrList(List<EquivalentAddressGroup> addrList) {

xds/src/main/java/io/grpc/xds/WeightedRoundRobinLoadBalancer.java

@@ -148,10 +148,8 @@ final class WeightedRoundRobinLoadBalancer extends MultiChildLoadBalancer {
   }
 
   @Override
-  protected ChildLbState createChildLbState(Object key, Object policyConfig,
+  protected ChildLbState createChildLbState(Object key) {
-      ResolvedAddresses unused) {
+    return new WeightedChildLbState(key, pickFirstLbProvider);
-    ChildLbState childLbState = new WeightedChildLbState(key, pickFirstLbProvider, policyConfig);
-    return childLbState;
   }
 
   @Override
@@ -289,9 +287,8 @@ final class WeightedRoundRobinLoadBalancer extends MultiChildLoadBalancer {
 
     private OrcaReportListener orcaReportListener;
 
-    public WeightedChildLbState(
+    public WeightedChildLbState(Object key, LoadBalancerProvider policyProvider) {
-        Object key, LoadBalancerProvider policyProvider, Object childConfig) {
+      super(key, policyProvider);
-      super(key, policyProvider, childConfig);
     }
 
     @Override