proxy: consolidate ServicesHandler/EndpointsHandler into ProxyProvider

Proxies should be able to cleanly figure out when endpoints have been synced,
so make all ProxyProviders also implement EndpointsHandler and pass those
through to loadbalancers when required.

pkg/proxy/types.go

@@ -21,10 +21,14 @@ import (
 
 	"k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/kubernetes/pkg/proxy/config"
 )
 
 // ProxyProvider is the interface provided by proxier implementations.
 type ProxyProvider interface {
+	config.EndpointsHandler
+	config.ServiceHandler
+
 	// Sync immediately synchronizes the ProxyProvider's current state to proxy rules.
 	Sync()
 	// SyncLoop runs periodic work.