diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index 49f1a92dd061..c84992f952a0 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -648,12 +648,6 @@ uint64_t Navigator::HardwareConcurrency() {
   return rts->ClampedHardwareConcurrency();
 }
 
-void Navigator::RefreshMIMEArray() {
-  if (mMimeTypes) {
-    mMimeTypes->Refresh();
-  }
-}
-
 namespace {
 
 class VibrateWindowListener : public nsIDOMEventListener {
diff --git a/dom/base/Navigator.h b/dom/base/Navigator.h
index 9722f0c36bbe..e36cd43b76fd 100644
--- a/dom/base/Navigator.h
+++ b/dom/base/Navigator.h
@@ -96,8 +96,6 @@ class Navigator final : public nsISupports, public nsWrapperCache {
   void Invalidate();
   nsPIDOMWindowInner* GetWindow() const { return mWindow; }
 
-  void RefreshMIMEArray();
-
   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
 
   /**
diff --git a/dom/base/nsMimeTypeArray.h b/dom/base/nsMimeTypeArray.h
index 09681054d7d2..83c31559b656 100644
--- a/dom/base/nsMimeTypeArray.h
+++ b/dom/base/nsMimeTypeArray.h
@@ -34,8 +34,6 @@ class nsMimeTypeArray final : public nsISupports, public nsWrapperCache {
   virtual JSObject* WrapObject(JSContext* aCx,
                                JS::Handle<JSObject*> aGivenProto) override;
 
-  void Refresh() {}
-
   // MimeTypeArray WebIDL methods
   nsMimeType* Item(uint32_t index, mozilla::dom::CallerType aCallerType) {
     return nullptr;