--- a/dom/asmjscache/AsmJSCache.cpp
+++ b/dom/asmjscache/AsmJSCache.cpp
@@ -433,17 +433,17 @@ class ParentRunnable final
   , public PAsmJSCacheEntryParent
 {
 public:
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_NSIRUNNABLE
 
   ParentRunnable(const PrincipalInfo& aPrincipalInfo,
                  OpenMode aOpenMode,
-                 WriteParams aWriteParams)
+                 const WriteParams& aWriteParams)
   : mOwningEventTarget(GetCurrentThreadEventTarget()),
     mPrincipalInfo(aPrincipalInfo),
     mOpenMode(aOpenMode),
     mWriteParams(aWriteParams),
     mOperationMayProceed(true),
     mState(eInitial),
     mResult(JS::AsmJSCache_InternalError),
     mActorDestroyed(false),
@@ -1312,17 +1312,17 @@ public:
       }
     }
   };
 
   NS_DECL_NSIRUNNABLE
 
   ChildRunnable(nsIPrincipal* aPrincipal,
                 OpenMode aOpenMode,
-                WriteParams aWriteParams,
+                const WriteParams& aWriteParams,
                 ReadParams aReadParams)
   : mPrincipal(aPrincipal),
     mWriteParams(aWriteParams),
     mReadParams(aReadParams),
     mMutex("ChildRunnable::mMutex"),
     mCondVar(mMutex, "ChildRunnable::mCondVar"),
     mOpenMode(aOpenMode),
     mState(eInitial),