LibWeb: Make factory method of CSS::ResolvedCSSStyleDeclaration fallible

Author: https://github.com/kennethmyhra
Commit: 8fbd43cb27
Pull-request: https://github.com/SerenityOS/serenity/pull/17491
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/CSS/ResolvedCSSStyleDeclaration.cpp

@@ -20,9 +20,9 @@
 
 namespace Web::CSS {
 
-ResolvedCSSStyleDeclaration* ResolvedCSSStyleDeclaration::create(DOM::Element& element)
+WebIDL::ExceptionOr<JS::NonnullGCPtr<ResolvedCSSStyleDeclaration>> ResolvedCSSStyleDeclaration::create(DOM::Element& element)
 {
-    return element.realm().heap().allocate<ResolvedCSSStyleDeclaration>(element.realm(), element).release_allocated_value_but_fixme_should_propagate_errors();
+    return MUST_OR_THROW_OOM(element.realm().heap().allocate<ResolvedCSSStyleDeclaration>(element.realm(), element));
 }
 
 ResolvedCSSStyleDeclaration::ResolvedCSSStyleDeclaration(DOM::Element& element)