--- a/layout/style/nsDOMCSSAttrDeclaration.cpp
+++ b/layout/style/nsDOMCSSAttrDeclaration.cpp
@@ -171,19 +171,20 @@ nsDOMCSSAttributeDeclaration::GetCSSPars
   aCSSParseEnv.mBaseURI = mElement->GetBaseURIForStyleAttr();
   aCSSParseEnv.mPrincipal = mElement->NodePrincipal();
   aCSSParseEnv.mCSSLoader = doc->CSSLoader();
 }
 
 nsDOMCSSDeclaration::ServoCSSParsingEnvironment
 nsDOMCSSAttributeDeclaration::GetServoCSSParsingEnvironment() const
 {
-  ServoCSSParsingEnvironment parsingEnv(mElement->GetURLDataForStyleAttr(),
-    mElement->OwnerDoc()->GetCompatibilityMode());
-  return parsingEnv;
+  return {
+    mElement->GetURLDataForStyleAttr(),
+    mElement->OwnerDoc()->GetCompatibilityMode(),
+  };
 }
 
 NS_IMETHODIMP
 nsDOMCSSAttributeDeclaration::GetParentRule(nsIDOMCSSRule **aParent)
 {
   NS_ENSURE_ARG_POINTER(aParent);
 
   *aParent = nullptr;

--- a/layout/style/nsDOMCSSDeclaration.cpp
+++ b/layout/style/nsDOMCSSDeclaration.cpp
@@ -280,26 +280,30 @@ nsDOMCSSDeclaration::GetCSSParsingEnviro
   aCSSParseEnv.mCSSLoader = document ? document->CSSLoader() : nullptr;
 }
 
 /* static */ nsDOMCSSDeclaration::ServoCSSParsingEnvironment
 nsDOMCSSDeclaration::GetServoCSSParsingEnvironmentForRule(const css::Rule* aRule)
 {
   StyleSheet* sheet = aRule ? aRule->GetStyleSheet() : nullptr;
   if (!sheet) {
-    return ServoCSSParsingEnvironment(nullptr, eCompatibility_FullStandards);
+    return { nullptr, eCompatibility_FullStandards };
   }
 
   if (nsIDocument* document = aRule->GetDocument()) {
-    return ServoCSSParsingEnvironment(sheet->AsServo()->URLData(),
-      document->GetCompatibilityMode());
-  } else {
-    return ServoCSSParsingEnvironment(sheet->AsServo()->URLData(),
-                                      eCompatibility_FullStandards);
+    return {
+      sheet->AsServo()->URLData(),
+      document->GetCompatibilityMode(),
+    };
   }
+
+  return {
+    sheet->AsServo()->URLData(),
+    eCompatibility_FullStandards,
+  };
 }
 
 template<typename GeckoFunc, typename ServoFunc>
 nsresult
 nsDOMCSSDeclaration::ModifyDeclaration(GeckoFunc aGeckoFunc,
                                        ServoFunc aServoFunc)
 {
   DeclarationBlock* olddecl = GetCSSDeclaration(eOperation_Modify);

--- a/layout/style/nsDOMCSSDeclaration.h
+++ b/layout/style/nsDOMCSSDeclaration.h
@@ -144,22 +144,26 @@ protected:
                                  "reference; reference counting here has unacceptable "
                                  "performance overhead (see bug 649163)") mPrincipal;
     mozilla::css::Loader* MOZ_UNSAFE_REF("user of CSSParsingEnviroment must hold an owning "
                                          "reference; reference counting here has unacceptable "
                                          "performance overhead (see bug 649163)") mCSSLoader;
   };
 
   // Information neded to parse a declaration for Servo side.
-  struct MOZ_STACK_CLASS ServoCSSParsingEnvironment {
+  struct MOZ_STACK_CLASS ServoCSSParsingEnvironment
+  {
     mozilla::URLExtraData* mUrlExtraData;
     nsCompatibility mCompatMode;
 
-    ServoCSSParsingEnvironment(mozilla::URLExtraData* aUrlData, nsCompatibility aCompatMode)
-      : mUrlExtraData(aUrlData), mCompatMode(aCompatMode) {}
+    ServoCSSParsingEnvironment(mozilla::URLExtraData* aUrlData,
+                               nsCompatibility aCompatMode)
+      : mUrlExtraData(aUrlData)
+      , mCompatMode(aCompatMode)
+    {}
   };
 
   // On failure, mPrincipal should be set to null in aCSSParseEnv.
   // If mPrincipal is null, the other members may not be set to
   // anything meaningful.
   virtual void GetCSSParsingEnvironment(CSSParsingEnvironment& aCSSParseEnv) = 0;
 
   // mUrlExtraData returns URL data for parsing url values in