diff --git a/content/base/public/FragmentOrElement.h b/content/base/public/FragmentOrElement.h
index c53bf789467..95c7299a697 100644
--- a/content/base/public/FragmentOrElement.h
+++ b/content/base/public/FragmentOrElement.h
@@ -412,7 +412,7 @@ public:
     /**
      * Web components custom element data.
      */
-    nsAutoPtr<CustomElementData> mCustomElementData;
+    nsRefPtr<CustomElementData> mCustomElementData;
   };
 
 protected:
diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index 9d06af8500b..18833741570 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -5844,12 +5844,7 @@ nsDocument::ProcessTopElementQueue(bool aIsBaseQueue)
 {
   MOZ_ASSERT(nsContentUtils::IsSafeToRunScript());
 
-  if (sProcessingStack.isNothing()) {
-    // If XPCOM shutdown has reset the processing stack, don't do anything.
-    return;
-  }
-
-  nsTArray<CustomElementData*>& stack = *sProcessingStack;
+  nsTArray<nsRefPtr<CustomElementData>>& stack = *sProcessingStack;
   uint32_t firstQueue = stack.LastIndexOf((CustomElementData*) nullptr);
 
   if (aIsBaseQueue && firstQueue != 0) {
@@ -5886,7 +5881,7 @@ nsDocument::RegisterEnabled()
 }
 
 // static
-Maybe<nsTArray<mozilla::dom::CustomElementData*>>
+Maybe<nsTArray<nsRefPtr<mozilla::dom::CustomElementData>>>
 nsDocument::sProcessingStack;
 
 // static
diff --git a/content/base/src/nsDocument.h b/content/base/src/nsDocument.h
index dcb52223036..3a9f8a3deab 100644
--- a/content/base/src/nsDocument.h
+++ b/content/base/src/nsDocument.h
@@ -325,6 +325,8 @@ private:
 // being created flag.
 struct CustomElementData
 {
+  NS_INLINE_DECL_REFCOUNTING(CustomElementData)
+
   explicit CustomElementData(nsIAtom* aType);
   // Objects in this array are transient and empty after each microtask
   // checkpoint.
@@ -346,6 +348,9 @@ struct CustomElementData
 
   // Empties the callback queue.
   void RunCallbackQueue();
+
+private:
+  virtual ~CustomElementData() {}
 };
 
 // The required information for a custom element as defined in:
@@ -1520,7 +1525,7 @@ private:
   // CustomElementData in this array, separated by nullptr that
   // represent the boundaries of the items in the stack. The first
   // queue in the stack is the base element queue.
-  static mozilla::Maybe<nsTArray<mozilla::dom::CustomElementData*>> sProcessingStack;
+  static mozilla::Maybe<nsTArray<nsRefPtr<mozilla::dom::CustomElementData>>> sProcessingStack;
 
   // Flag to prevent re-entrance into base element queue as described in the
   // custom elements speicification.