Add support for Pull Queues to prod implementation.

filter/featureBreaker/tq.go

Index: filter/featureBreaker/tq.go
diff --git a/filter/featureBreaker/tq.go b/filter/featureBreaker/tq.go
index c5c84482c67e91159d8ae844530c8c16c2004df1..31d58d7f6f4add0ae9d9b63e87a7c4c5e3faf8e3 100644
--- a/filter/featureBreaker/tq.go
+++ b/filter/featureBreaker/tq.go
@@ -5,6 +5,8 @@
 package featureBreaker
 
 import (
+	"time"
+
 	"golang.org/x/net/context"
 
 	tq "github.com/luci/gae/service/taskqueue"
@@ -26,6 +28,32 @@ func (t *tqState) DeleteMulti(tasks []*tq.Task, queueName string, cb tq.RawCB) e
 	return t.run(func() error { return t.tq.DeleteMulti(tasks, queueName, cb) })
 }
 
+func (t *tqState) Lease(maxTasks int, queueName string, leaseTime time.Duration) (tasks []*tq.Task, err error) {
+	err = t.run(func() (err error) {
+		tasks, err = t.tq.Lease(maxTasks, queueName, leaseTime)
+		return
+	})
+	if err != nil {
+		tasks = nil
+	}
+	return
+}
+
+func (t *tqState) LeaseByTag(maxTasks int, queueName string, leaseTime time.Duration, tag string) (tasks []*tq.Task, err error) {
+	err = t.run(func() (err error) {
+		tasks, err = t.tq.LeaseByTag(maxTasks, queueName, leaseTime, tag)
+		return
+	})
+	if err != nil {
+		tasks = nil
+	}
+	return
+}
+
+func (t *tqState) ModifyLease(task *tq.Task, queueName string, leaseTime time.Duration) error {
+	return t.run(func() error { return t.tq.ModifyLease(task, queueName, leaseTime) })
+}
+
 func (t *tqState) Purge(queueName string) error {
 	return t.run(func() error { return t.tq.Purge(queueName) })
 }