--- a/layout/style/CSSMozDocumentRule.cpp
+++ b/layout/style/CSSMozDocumentRule.cpp
@@ -23,52 +23,38 @@ CSSMozDocumentRule::WrapObject(JSContext
 bool
 CSSMozDocumentRule::Match(nsIDocument* aDoc,
                           nsIURI* aDocURI,
                           const nsACString& aDocURISpec,
                           const nsACString& aPattern,
                           DocumentMatchingFunction aMatchingFunction)
 {
   switch (aMatchingFunction) {
-    case DocumentMatchingFunction::URL: {
-      if (aDocURISpec == aPattern) {
-        return true;
-      }
-    } break;
-    case DocumentMatchingFunction::URLPrefix: {
-      if (StringBeginsWith(aDocURISpec, aPattern)) {
-        return true;
-      }
-    } break;
+    case DocumentMatchingFunction::URL:
+      return aDocURISpec == aPattern;
+    case DocumentMatchingFunction::URLPrefix:
+      return StringBeginsWith(aDocURISpec, aPattern);
     case DocumentMatchingFunction::Domain: {
       nsAutoCString host;
       if (aDocURI) {
         aDocURI->GetHost(host);
       }
       int32_t lenDiff = host.Length() - aPattern.Length();
       if (lenDiff == 0) {
-        if (host == aPattern) {
-          return true;
-        }
-      } else {
-        if (StringEndsWith(host, aPattern) &&
-            host.CharAt(lenDiff - 1) == '.') {
-          return true;
-        }
+        return host == aPattern;
       }
-    } break;
+      return StringEndsWith(host, aPattern) && host.CharAt(lenDiff - 1) == '.';
+    }
     case DocumentMatchingFunction::RegExp: {
       NS_ConvertUTF8toUTF16 spec(aDocURISpec);
       NS_ConvertUTF8toUTF16 regex(aPattern);
-      if (nsContentUtils::IsPatternMatching(spec, regex, aDoc)) {
-        return true;
-      }
-    } break;
+      return nsContentUtils::IsPatternMatching(spec, regex, aDoc);
+    }
   }
-
+  MOZ_ASSERT_UNREACHABLE("Unknown matching function");
   return false;
 }
 
 CSSMozDocumentRule::CSSMozDocumentRule(RefPtr<RawServoMozDocumentRule> aRawRule,
                                        StyleSheet* aSheet,
                                        css::Rule* aParentRule,
                                        uint32_t aLine,
                                        uint32_t aColumn)