--- a/uriloader/exthandler/ExternalHelperAppParent.cpp
+++ b/uriloader/exthandler/ExternalHelperAppParent.cpp
@@ -36,17 +36,19 @@ NS_IMPL_ISUPPORTS_INHERITED(ExternalHelp
                             nsIResumableChannel,
                             nsIStreamListener)
 
 ExternalHelperAppParent::ExternalHelperAppParent(
     const OptionalURIParams& uri,
     const int64_t& aContentLength)
   : mURI(DeserializeURI(uri))
   , mPending(false)
+#ifdef DEBUG
   , mDiverted(false)
+#endif
   , mIPCClosed(false)
   , mLoadFlags(0)
   , mStatus(NS_OK)
   , mContentLength(aContentLength)
 {
 }
 
 void
@@ -154,17 +156,19 @@ ExternalHelperAppParent::RecvOnStopReque
 }
 
 bool
 ExternalHelperAppParent::RecvDivertToParentUsing(PChannelDiverterParent* diverter)
 {
   MOZ_ASSERT(diverter);
   auto p = static_cast<mozilla::net::ChannelDiverterParent*>(diverter);
   p->DivertTo(this);
+#ifdef DEBUG
   mDiverted = true;
+#endif
   Unused << p->Send__delete__(p);
   return true;
 }
 
 //
 // nsIStreamListener
 //
 

--- a/uriloader/exthandler/ExternalHelperAppParent.h
+++ b/uriloader/exthandler/ExternalHelperAppParent.h
@@ -73,17 +73,19 @@ protected:
 
   virtual void ActorDestroy(ActorDestroyReason why) override;
   void Delete();
 
 private:
   nsCOMPtr<nsIStreamListener> mListener;
   nsCOMPtr<nsIURI> mURI;
   bool mPending;
-  DebugOnly<bool> mDiverted;
+#ifdef DEBUG
+  bool mDiverted;
+#endif
   bool mIPCClosed;
   nsLoadFlags mLoadFlags;
   nsresult mStatus;
   int64_t mContentLength;
   uint32_t mContentDisposition;
   nsString mContentDispositionFilename;
   nsCString mContentDispositionHeader;
   nsCString mEntityID;