--- a/js/xpconnect/src/XPCJSContext.cpp
+++ b/js/xpconnect/src/XPCJSContext.cpp
@@ -779,29 +779,16 @@ XPCJSContext::FinalizeCallback(JSFreeOp*
 
             break;
         }
         case JSFINALIZE_COLLECTION_END:
         {
             MOZ_ASSERT(!self->mGCIsRunning, "bad state");
             self->mGCIsRunning = true;
 
-            // We use this occasion to mark and sweep NativeInterfaces,
-            // NativeSets, and the WrappedNativeJSClasses...
-
-            // Do the marking...
-            XPCWrappedNativeScope::MarkAllWrappedNativesAndProtos();
-
-            // Mark the sets used in the call contexts. There is a small
-            // chance that a wrapper's set will change *while* a call is
-            // happening which uses that wrapper's old interfface set. So,
-            // we need to do this marking to avoid collecting those sets
-            // that might no longer be otherwise reachable from the wrappers
-            // or the wrapperprotos.
-
             // Skip this part if XPConnect is shutting down. We get into
             // bad locking problems with the thread iteration otherwise.
             if (!nsXPConnect::XPConnect()->IsShuttingDown()) {
 
                 // Mark those AutoMarkingPtr lists!
                 if (AutoMarkingPtr* roots = Get()->mAutoRoots)
                     roots->MarkAfterJSFinalizeAll();
             }

--- a/js/xpconnect/src/XPCWrappedNativeScope.cpp
+++ b/js/xpconnect/src/XPCWrappedNativeScope.cpp
@@ -571,34 +571,16 @@ XPCWrappedNativeScope::UpdateWeakPointer
         if (cur)
             prev = cur;
         cur = next;
     }
 }
 
 // static
 void
-XPCWrappedNativeScope::MarkAllWrappedNativesAndProtos()
-{
-    for (XPCWrappedNativeScope* cur = gScopes; cur; cur = cur->mNext) {
-        for (auto i = cur->mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
-            auto entry = static_cast<Native2WrappedNativeMap::Entry*>(i.Get());
-            entry->value->Mark();
-        }
-        // We need to explicitly mark all the protos too because some protos may be
-        // alive in the hashtable but not currently in use by any wrapper
-        for (auto i = cur->mWrappedNativeProtoMap->Iter(); !i.Done(); i.Next()) {
-            auto entry = static_cast<ClassInfo2WrappedNativeProtoMap::Entry*>(i.Get());
-            entry->value->Mark();
-        }
-    }
-}
-
-// static
-void
 XPCWrappedNativeScope::SweepAllWrappedNativeTearOffs()
 {
     for (XPCWrappedNativeScope* cur = gScopes; cur; cur = cur->mNext) {
         for (auto i = cur->mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
             auto entry = static_cast<Native2WrappedNativeMap::Entry*>(i.Get());
             entry->value->SweepTearOffs();
         }
     }

--- a/js/xpconnect/src/xpcprivate.h
+++ b/js/xpconnect/src/xpcprivate.h
@@ -924,19 +924,16 @@ public:
         if (mXrayExpandos.initialized())
             mXrayExpandos.trace(trc);
     }
 
     static void
     SuspectAllWrappers(XPCJSContext* cx, nsCycleCollectionNoteRootCallback& cb);
 
     static void
-    MarkAllWrappedNativesAndProtos();
-
-    static void
     SweepAllWrappedNativeTearOffs();
 
     static void
     UpdateWeakPointersAfterGC(XPCJSContext* cx);
 
     static void
     KillDyingScopes();
 
@@ -1890,20 +1887,17 @@ public:
 
     inline bool HasInterfaceNoQI(const nsIID& iid);
 
     XPCWrappedNativeTearOff* FindTearOff(XPCNativeInterface* aInterface,
                                          bool needJSObject = false,
                                          nsresult* pError = nullptr);
     XPCWrappedNativeTearOff* FindTearOff(const nsIID& iid);
 
-    void Mark() const
-    {
-        if (HasProto()) GetProto()->Mark();
-    }
+    void Mark() const {}
 
     inline void TraceInside(JSTracer* trc) {
         if (HasProto())
             GetProto()->TraceSelf(trc);
         else
             GetScope()->TraceSelf(trc);
         if (mFlatJSObject && JS_IsGlobalObject(mFlatJSObject))
         {