[gnome-builder] pipeline: chain cancellable without creating secondary

[Christian Hergert <chergert src gnome org>]

commit aecd61e94b022de39305d831b8b3c6e0db6fa1d7
Author: Christian Hergert <chergert redhat com>
Date:   Wed Jan 10 22:05:04 2018 -0800

    pipeline: chain cancellable without creating secondary

 src/libide/buildsystem/ide-build-pipeline.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/src/libide/buildsystem/ide-build-pipeline.c b/src/libide/buildsystem/ide-build-pipeline.c
index 9fb4c84..6e7e6d6 100644
--- a/src/libide/buildsystem/ide-build-pipeline.c
+++ b/src/libide/buildsystem/ide-build-pipeline.c
@@ -1540,13 +1540,14 @@ ide_build_pipeline_build_async (IdeBuildPipeline    *self,
                                 gpointer             user_data)
 {
   g_autoptr(GTask) task = NULL;
-  g_autoptr(GCancellable) local_cancellable = NULL;
   TaskData *task_data;
 
   IDE_ENTRY;
 
-  if (cancellable == NULL)
-    cancellable = local_cancellable = g_cancellable_new ();
+  g_return_if_fail (IDE_IS_BUILD_PIPELINE (self));
+  g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
+
+  cancellable = dzl_cancellable_chain (cancellable, self->cancellable);
 
   task = g_task_new (self, cancellable, callback, user_data);
   g_task_set_source_tag (task, ide_build_pipeline_build_async);