[librsvg: 23/36] filters/merge: remove interior mutability

[Federico Mena Quintero <federico src gnome org>]

commit 0949250c3c9e3f8bfded829343e3ac136ba3bb07
Author: Paolo Borelli <pborelli gnome org>
Date:   Sun Jun 30 16:28:49 2019 +0200

    filters/merge: remove interior mutability

 rsvg_internals/src/filters/merge.rs | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)
---
diff --git a/rsvg_internals/src/filters/merge.rs b/rsvg_internals/src/filters/merge.rs
index 7a678e7e..c0118923 100644
--- a/rsvg_internals/src/filters/merge.rs
+++ b/rsvg_internals/src/filters/merge.rs
@@ -1,5 +1,3 @@
-use std::cell::RefCell;
-
 use cairo::{self, ImageSurface};
 use markup5ever::local_name;
 
@@ -21,7 +19,7 @@ pub struct Merge {
 /// The `<feMergeNode>` element.
 #[derive(Default)]
 pub struct MergeNode {
-    in_: RefCell<Option<Input>>,
+    in_: Option<Input>,
 }
 
 impl Default for Merge {
@@ -48,9 +46,7 @@ impl NodeTrait for MergeNode {
     fn set_atts(&mut self, _parent: Option<&RsvgNode>, pbag: &PropertyBag<'_>) -> NodeResult {
         for (attr, value) in pbag.iter() {
             match attr {
-                local_name!("in") => {
-                    self.in_.replace(Some(Input::parse(attr, value)?));
-                }
+                local_name!("in") => self.in_ = Some(Input::parse(attr, value)?),
                 _ => (),
             }
         }
@@ -67,7 +63,7 @@ impl MergeNode {
         bounds: IRect,
         output_surface: Option<SharedImageSurface>,
     ) -> Result<SharedImageSurface, FilterError> {
-        let input = ctx.get_input(draw_ctx, self.in_.borrow().as_ref())?;
+        let input = ctx.get_input(draw_ctx, self.in_.as_ref())?;
 
         if output_surface.is_none() {
             return Ok(input.surface().clone());
@@ -131,7 +127,7 @@ impl Filter for Merge {
 
             let input = ctx.get_input(
                 draw_ctx,
-                child.borrow().get_impl::<MergeNode>().in_.borrow().as_ref(),
+                child.borrow().get_impl::<MergeNode>().in_.as_ref(),
             )?;
             bounds = bounds.add_input(&input);
         }