Add support for Pull Queues to prod implementation.

service/taskqueue/raw_interface.go

Index: service/taskqueue/raw_interface.go
diff --git a/service/taskqueue/raw_interface.go b/service/taskqueue/raw_interface.go
index 14aa920dce35ed1ff32b74426a759a7e61031c15..5d52fc6ac76c34816034bc99d80e1a0a8b54ce93 100644
--- a/service/taskqueue/raw_interface.go
+++ b/service/taskqueue/raw_interface.go
@@ -26,6 +26,10 @@ type RawInterface interface {
 	AddMulti(tasks []*Task, queueName string, cb RawTaskCB) error
 	DeleteMulti(tasks []*Task, queueName string, cb RawCB) error
 
+	Lease(maxTasks int, queueName string, leaseTime int) ([]*Task, error)
+	LeaseByTag(maxTasks int, queueName string, leaseTime int, tag string) ([]*Task, error)
+	ModifyLease(task *Task, queueName string, leaseTime int) error
+
 	Purge(queueName string) error
 
 	Stats(queueNames []string, cb RawStatsCB) error