[librsvg] filter: shorten code

[Paolo Borelli <pborelli src gnome org>]

commit 5a40d4b457ae9f2107cf6e36b7957ef48cdf198b
Author: Paolo Borelli <pborelli gnome org>
Date:   Sat Apr 18 09:11:02 2020 +0200

    filter: shorten code

 rsvg_internals/src/drawing_ctx.rs | 7 +------
 rsvg_internals/src/filters/mod.rs | 5 ++++-
 2 files changed, 5 insertions(+), 7 deletions(-)
---
diff --git a/rsvg_internals/src/drawing_ctx.rs b/rsvg_internals/src/drawing_ctx.rs
index 1e876144..142bfffb 100644
--- a/rsvg_internals/src/drawing_ctx.rs
+++ b/rsvg_internals/src/drawing_ctx.rs
@@ -758,14 +758,9 @@ impl DrawingCtx {
         match acquired_nodes.acquire(filter_uri) {
             Ok(acquired) => {
                 let filter_node = acquired.get();
-                let filter_elt = filter_node.borrow_element();
 
-                match *filter_elt {
+                match *filter_node.borrow_element() {
                     Element::Filter(_) => {
-                        if filter_elt.is_in_error() {
-                            return Ok(child_surface);
-                        }
-
                         return filters::render(
                             &filter_node,
                             values,
diff --git a/rsvg_internals/src/filters/mod.rs b/rsvg_internals/src/filters/mod.rs
index eed87094..c098d7c8 100644
--- a/rsvg_internals/src/filters/mod.rs
+++ b/rsvg_internals/src/filters/mod.rs
@@ -279,7 +279,10 @@ pub fn render(
 ) -> Result<SharedImageSurface, RenderingError> {
     let filter_node = &*filter_node;
     assert!(is_element_of_type!(filter_node, Filter));
-    assert!(!filter_node.borrow_element().is_in_error());
+
+    if filter_node.borrow_element().is_in_error() {
+        return Ok(source_surface);
+    }
 
     let mut filter_ctx = FilterContext::new(
         filter_node,