diff --git a/vendor/google.golang.org/grpc/resolver_conn_wrapper.go b/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
new file mode 100644
index 0000000..6934905
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver_conn_wrapper.go
@@ -0,0 +1,168 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc
+
+import (
+	"fmt"
+	"strings"
+	"sync/atomic"
+
+	"google.golang.org/grpc/grpclog"
+	"google.golang.org/grpc/internal/channelz"
+	"google.golang.org/grpc/resolver"
+)
+
+// ccResolverWrapper is a wrapper on top of cc for resolvers.
+// It implements resolver.ClientConnection interface.
+type ccResolverWrapper struct {
+	cc       *ClientConn
+	resolver resolver.Resolver
+	addrCh   chan []resolver.Address
+	scCh     chan string
+	done     uint32 // accessed atomically; set to 1 when closed.
+	curState resolver.State
+}
+
+// split2 returns the values from strings.SplitN(s, sep, 2).
+// If sep is not found, it returns ("", "", false) instead.
+func split2(s, sep string) (string, string, bool) {
+	spl := strings.SplitN(s, sep, 2)
+	if len(spl) < 2 {
+		return "", "", false
+	}
+	return spl[0], spl[1], true
+}
+
+// parseTarget splits target into a struct containing scheme, authority and
+// endpoint.
+//
+// If target is not a valid scheme://authority/endpoint, it returns {Endpoint:
+// target}.
+func parseTarget(target string) (ret resolver.Target) {
+	var ok bool
+	ret.Scheme, ret.Endpoint, ok = split2(target, "://")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
+	ret.Authority, ret.Endpoint, ok = split2(ret.Endpoint, "/")
+	if !ok {
+		return resolver.Target{Endpoint: target}
+	}
+	return ret
+}
+
+// newCCResolverWrapper parses cc.target for scheme and gets the resolver
+// builder for this scheme and builds the resolver. The monitoring goroutine
+// for it is not started yet and can be created by calling start().
+//
+// If withResolverBuilder dial option is set, the specified resolver will be
+// used instead.
+func newCCResolverWrapper(cc *ClientConn) (*ccResolverWrapper, error) {
+	rb := cc.dopts.resolverBuilder
+	if rb == nil {
+		return nil, fmt.Errorf("could not get resolver for scheme: %q", cc.parsedTarget.Scheme)
+	}
+
+	ccr := &ccResolverWrapper{
+		cc:     cc,
+		addrCh: make(chan []resolver.Address, 1),
+		scCh:   make(chan string, 1),
+	}
+
+	var err error
+	ccr.resolver, err = rb.Build(cc.parsedTarget, ccr, resolver.BuildOption{DisableServiceConfig: cc.dopts.disableServiceConfig})
+	if err != nil {
+		return nil, err
+	}
+	return ccr, nil
+}
+
+func (ccr *ccResolverWrapper) resolveNow(o resolver.ResolveNowOption) {
+	ccr.resolver.ResolveNow(o)
+}
+
+func (ccr *ccResolverWrapper) close() {
+	ccr.resolver.Close()
+	atomic.StoreUint32(&ccr.done, 1)
+}
+
+func (ccr *ccResolverWrapper) isDone() bool {
+	return atomic.LoadUint32(&ccr.done) == 1
+}
+
+func (ccr *ccResolverWrapper) UpdateState(s resolver.State) {
+	if ccr.isDone() {
+		return
+	}
+	grpclog.Infof("ccResolverWrapper: sending update to cc: %v", s)
+	if channelz.IsOn() {
+		ccr.addChannelzTraceEvent(s)
+	}
+	ccr.cc.updateResolverState(s)
+	ccr.curState = s
+}
+
+// NewAddress is called by the resolver implementation to send addresses to gRPC.
+func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
+	if ccr.isDone() {
+		return
+	}
+	grpclog.Infof("ccResolverWrapper: sending new addresses to cc: %v", addrs)
+	if channelz.IsOn() {
+		ccr.addChannelzTraceEvent(resolver.State{Addresses: addrs, ServiceConfig: ccr.curState.ServiceConfig})
+	}
+	ccr.curState.Addresses = addrs
+	ccr.cc.updateResolverState(ccr.curState)
+}
+
+// NewServiceConfig is called by the resolver implementation to send service
+// configs to gRPC.
+func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
+	if ccr.isDone() {
+		return
+	}
+	grpclog.Infof("ccResolverWrapper: got new service config: %v", sc)
+	c, err := parseServiceConfig(sc)
+	if err != nil {
+		return
+	}
+	if channelz.IsOn() {
+		ccr.addChannelzTraceEvent(resolver.State{Addresses: ccr.curState.Addresses, ServiceConfig: c})
+	}
+	ccr.curState.ServiceConfig = c
+	ccr.cc.updateResolverState(ccr.curState)
+}
+
+func (ccr *ccResolverWrapper) addChannelzTraceEvent(s resolver.State) {
+	var updates []string
+	oldSC, oldOK := ccr.curState.ServiceConfig.(*ServiceConfig)
+	newSC, newOK := s.ServiceConfig.(*ServiceConfig)
+	if oldOK != newOK || (oldOK && newOK && oldSC.rawJSONString != newSC.rawJSONString) {
+		updates = append(updates, "service config updated")
+	}
+	if len(ccr.curState.Addresses) > 0 && len(s.Addresses) == 0 {
+		updates = append(updates, "resolver returned an empty address list")
+	} else if len(ccr.curState.Addresses) == 0 && len(s.Addresses) > 0 {
+		updates = append(updates, "resolver returned new addresses")
+	}
+	channelz.AddTraceEvent(ccr.cc.channelzID, &channelz.TraceEventDesc{
+		Desc:     fmt.Sprintf("Resolver state updated: %+v (%v)", s, strings.Join(updates, "; ")),
+		Severity: channelz.CtINFO,
+	})
+}