diff --git a/vendor/google.golang.org/grpc/picker_wrapper.go b/vendor/google.golang.org/grpc/picker_wrapper.go
index 45baa2a..0044789 100644
--- a/vendor/google.golang.org/grpc/picker_wrapper.go
+++ b/vendor/google.golang.org/grpc/picker_wrapper.go
@@ -20,6 +20,7 @@
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"sync"
 
@@ -31,49 +32,78 @@
 	"google.golang.org/grpc/status"
 )
 
+// v2PickerWrapper wraps a balancer.Picker while providing the
+// balancer.V2Picker API.  It requires a pickerWrapper to generate errors
+// including the latest connectionError.  To be deleted when balancer.Picker is
+// updated to the balancer.V2Picker API.
+type v2PickerWrapper struct {
+	picker  balancer.Picker
+	connErr *connErr
+}
+
+func (v *v2PickerWrapper) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
+	sc, done, err := v.picker.Pick(info.Ctx, info)
+	if err != nil {
+		if err == balancer.ErrTransientFailure {
+			return balancer.PickResult{}, balancer.TransientFailureError(fmt.Errorf("%v, latest connection error: %v", err, v.connErr.connectionError()))
+		}
+		return balancer.PickResult{}, err
+	}
+	return balancer.PickResult{SubConn: sc, Done: done}, nil
+}
+
 // pickerWrapper is a wrapper of balancer.Picker. It blocks on certain pick
 // actions and unblock when there's a picker update.
 type pickerWrapper struct {
 	mu         sync.Mutex
 	done       bool
 	blockingCh chan struct{}
-	picker     balancer.Picker
+	picker     balancer.V2Picker
 
-	// The latest connection happened.
-	connErrMu sync.Mutex
-	connErr   error
+	// The latest connection error.  TODO: remove when V1 picker is deprecated;
+	// balancer should be responsible for providing the error.
+	*connErr
 }
 
-func newPickerWrapper() *pickerWrapper {
-	bp := &pickerWrapper{blockingCh: make(chan struct{})}
-	return bp
+type connErr struct {
+	mu  sync.Mutex
+	err error
 }
 
-func (bp *pickerWrapper) updateConnectionError(err error) {
-	bp.connErrMu.Lock()
-	bp.connErr = err
-	bp.connErrMu.Unlock()
+func (c *connErr) updateConnectionError(err error) {
+	c.mu.Lock()
+	c.err = err
+	c.mu.Unlock()
 }
 
-func (bp *pickerWrapper) connectionError() error {
-	bp.connErrMu.Lock()
-	err := bp.connErr
-	bp.connErrMu.Unlock()
+func (c *connErr) connectionError() error {
+	c.mu.Lock()
+	err := c.err
+	c.mu.Unlock()
 	return err
 }
 
+func newPickerWrapper() *pickerWrapper {
+	return &pickerWrapper{blockingCh: make(chan struct{}), connErr: &connErr{}}
+}
+
 // updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
-func (bp *pickerWrapper) updatePicker(p balancer.Picker) {
-	bp.mu.Lock()
-	if bp.done {
-		bp.mu.Unlock()
+func (pw *pickerWrapper) updatePicker(p balancer.Picker) {
+	pw.updatePickerV2(&v2PickerWrapper{picker: p, connErr: pw.connErr})
+}
+
+// updatePicker is called by UpdateBalancerState. It unblocks all blocked pick.
+func (pw *pickerWrapper) updatePickerV2(p balancer.V2Picker) {
+	pw.mu.Lock()
+	if pw.done {
+		pw.mu.Unlock()
 		return
 	}
-	bp.picker = p
-	// bp.blockingCh should never be nil.
-	close(bp.blockingCh)
-	bp.blockingCh = make(chan struct{})
-	bp.mu.Unlock()
+	pw.picker = p
+	// pw.blockingCh should never be nil.
+	close(pw.blockingCh)
+	pw.blockingCh = make(chan struct{})
+	pw.mu.Unlock()
 }
 
 func doneChannelzWrapper(acw *acBalancerWrapper, done func(balancer.DoneInfo)) func(balancer.DoneInfo) {
@@ -100,83 +130,85 @@
 // - the current picker returns other errors and failfast is false.
 // - the subConn returned by the current picker is not READY
 // When one of these situations happens, pick blocks until the picker gets updated.
-func (bp *pickerWrapper) pick(ctx context.Context, failfast bool, opts balancer.PickOptions) (transport.ClientTransport, func(balancer.DoneInfo), error) {
+func (pw *pickerWrapper) pick(ctx context.Context, failfast bool, info balancer.PickInfo) (transport.ClientTransport, func(balancer.DoneInfo), error) {
 	var ch chan struct{}
 
+	var lastPickErr error
 	for {
-		bp.mu.Lock()
-		if bp.done {
-			bp.mu.Unlock()
+		pw.mu.Lock()
+		if pw.done {
+			pw.mu.Unlock()
 			return nil, nil, ErrClientConnClosing
 		}
 
-		if bp.picker == nil {
-			ch = bp.blockingCh
+		if pw.picker == nil {
+			ch = pw.blockingCh
 		}
-		if ch == bp.blockingCh {
+		if ch == pw.blockingCh {
 			// This could happen when either:
-			// - bp.picker is nil (the previous if condition), or
+			// - pw.picker is nil (the previous if condition), or
 			// - has called pick on the current picker.
-			bp.mu.Unlock()
+			pw.mu.Unlock()
 			select {
 			case <-ctx.Done():
-				if connectionErr := bp.connectionError(); connectionErr != nil {
-					switch ctx.Err() {
-					case context.DeadlineExceeded:
-						return nil, nil, status.Errorf(codes.DeadlineExceeded, "latest connection error: %v", connectionErr)
-					case context.Canceled:
-						return nil, nil, status.Errorf(codes.Canceled, "latest connection error: %v", connectionErr)
-					}
+				var errStr string
+				if lastPickErr != nil {
+					errStr = "latest balancer error: " + lastPickErr.Error()
+				} else if connectionErr := pw.connectionError(); connectionErr != nil {
+					errStr = "latest connection error: " + connectionErr.Error()
+				} else {
+					errStr = ctx.Err().Error()
 				}
-				return nil, nil, ctx.Err()
+				switch ctx.Err() {
+				case context.DeadlineExceeded:
+					return nil, nil, status.Error(codes.DeadlineExceeded, errStr)
+				case context.Canceled:
+					return nil, nil, status.Error(codes.Canceled, errStr)
+				}
 			case <-ch:
 			}
 			continue
 		}
 
-		ch = bp.blockingCh
-		p := bp.picker
-		bp.mu.Unlock()
+		ch = pw.blockingCh
+		p := pw.picker
+		pw.mu.Unlock()
 
-		subConn, done, err := p.Pick(ctx, opts)
+		pickResult, err := p.Pick(info)
 
 		if err != nil {
-			switch err {
-			case balancer.ErrNoSubConnAvailable:
+			if err == balancer.ErrNoSubConnAvailable {
 				continue
-			case balancer.ErrTransientFailure:
+			}
+			if tfe, ok := err.(interface{ IsTransientFailure() bool }); ok && tfe.IsTransientFailure() {
 				if !failfast {
+					lastPickErr = err
 					continue
 				}
-				return nil, nil, status.Errorf(codes.Unavailable, "%v, latest connection error: %v", err, bp.connectionError())
-			case context.DeadlineExceeded:
-				return nil, nil, status.Error(codes.DeadlineExceeded, err.Error())
-			case context.Canceled:
-				return nil, nil, status.Error(codes.Canceled, err.Error())
-			default:
-				if _, ok := status.FromError(err); ok {
-					return nil, nil, err
-				}
-				// err is some other error.
-				return nil, nil, status.Error(codes.Unknown, err.Error())
+				return nil, nil, status.Error(codes.Unavailable, err.Error())
 			}
+			if _, ok := status.FromError(err); ok {
+				return nil, nil, err
+			}
+			// err is some other error.
+			return nil, nil, status.Error(codes.Unknown, err.Error())
 		}
 
-		acw, ok := subConn.(*acBalancerWrapper)
+		acw, ok := pickResult.SubConn.(*acBalancerWrapper)
 		if !ok {
 			grpclog.Error("subconn returned from pick is not *acBalancerWrapper")
 			continue
 		}
 		if t, ok := acw.getAddrConn().getReadyTransport(); ok {
 			if channelz.IsOn() {
-				return t, doneChannelzWrapper(acw, done), nil
+				return t, doneChannelzWrapper(acw, pickResult.Done), nil
 			}
-			return t, done, nil
+			return t, pickResult.Done, nil
 		}
-		if done != nil {
+		if pickResult.Done != nil {
 			// Calling done with nil error, no bytes sent and no bytes received.
 			// DoneInfo with default value works.
-			done(balancer.DoneInfo{})
+			pickResult.Done(balancer.DoneInfo{})
 		}
 		grpclog.Infof("blockingPicker: the picked transport is not ready, loop back to repick")
 		// If ok == false, ac.state is not READY.
@@ -186,12 +218,12 @@
 	}
 }
 
-func (bp *pickerWrapper) close() {
-	bp.mu.Lock()
-	defer bp.mu.Unlock()
-	if bp.done {
+func (pw *pickerWrapper) close() {
+	pw.mu.Lock()
+	defer pw.mu.Unlock()
+	if pw.done {
 		return
 	}
-	bp.done = true
-	close(bp.blockingCh)
+	pw.done = true
+	close(pw.blockingCh)
 }