logdog: Use gRPC credentials when creating PubSub client, not http.Client.

logdog/appengine/coordinator/archivalPublisher.go

Index: logdog/appengine/coordinator/archivalPublisher.go
diff --git a/logdog/appengine/coordinator/archivalPublisher.go b/logdog/appengine/coordinator/archivalPublisher.go
index 68b5343ed4396ab6fb68486963bb57d0a96d2a48..fd17b34a8b37f5ada8b9c3b114186c87c9e0ef34 100644
--- a/logdog/appengine/coordinator/archivalPublisher.go
+++ b/logdog/appengine/coordinator/archivalPublisher.go
@@ -17,6 +17,9 @@ import (
 
 // ArchivalPublisher is capable of publishing archival requests.
 type ArchivalPublisher interface {
+	// Close shutdowns this publisher, releasing all its resources.
+	Close() error
+
 	// Publish publishes the supplied ArchiveTask.
 	Publish(context.Context, *logdog.ArchiveTask) error
 
@@ -26,6 +29,9 @@ type ArchivalPublisher interface {
 }
 
 type pubsubArchivalPublisher struct {
+	// client is Pub/Sub client used by the publisher.
+	client *gcps.Client
+
 	// topic is the authenticated Pub/Sub topic handle to publish to.
 	topic *gcps.Topic
 
@@ -34,6 +40,10 @@ type pubsubArchivalPublisher struct {
 	publishIndexFunc func() uint64
 }
 
+func (p *pubsubArchivalPublisher) Close() error {
+	return p.client.Close()
+}
+
 func (p *pubsubArchivalPublisher) Publish(c context.Context, t *logdog.ArchiveTask) error {
 	d, err := proto.Marshal(t)
 	if err != nil {