Fix missing/broken ds.Stop handling in raw DS.

filter/count/count.go

Index: filter/count/count.go
diff --git a/filter/count/count.go b/filter/count/count.go
index d3ff220497037071f56fb9a17492b29266e0f48a..a00321084e37614e41003eb92345e583ab301692 100644
--- a/filter/count/count.go
+++ b/filter/count/count.go
@@ -11,6 +11,8 @@ package count
 import (
 	"fmt"
 	"sync/atomic"
+
+	"github.com/luci/luci-go/common/errors"
 )
 
 type counter struct {
@@ -62,3 +64,10 @@ func (e *Entry) up(errs ...error) error {
 	}
 	return err
 }
+
+// upFilter calls "up", converting the filtered errors into nil. The filtering
+// does not impact the original error, which is returned directly.
+func (e *Entry) upFilter(err, filter error, filterMore ...error) error {

[iannucci, 2016/04/01 02:45:42]

can't this just be upFilterStop? Does it ever filter anything else?

[dnj, 2016/04/01 21:41:05]

Done.

+	e.up(errors.Filter(err, filter, filterMore...))
+	return err
+}