[gtk] GskTransform: add assertions to make normalize_angle() intentions clear

[Matthias Clasen <matthiasc src gnome org>]

commit cbb05a3eabdf3fd57ed8ff2943bbae7812971e8e
Author: Timm Bäder <mail baedert org>
Date:   Sun Feb 2 13:20:40 2020 +0100

    GskTransform: add assertions to make normalize_angle() intentions  clear
    
    360deg should be expressed as 0deg and no angle should ever be
    negative.

 gsk/gsktransform.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gsk/gsktransform.c b/gsk/gsktransform.c
index 5d9d538d4c..f116b79acd 100644
--- a/gsk/gsktransform.c
+++ b/gsk/gsktransform.c
@@ -834,6 +834,9 @@ normalize_angle (float angle)
   if (f < 0)
     f = 360 + f;
 
+  g_assert (f < 360.0);
+  g_assert (f >= 0.0);
+
   return f;
 }