diff --git a/editor/libeditor/nsHTMLEditor.cpp b/editor/libeditor/nsHTMLEditor.cpp
index c881907d232..d732088b320 100644
--- a/editor/libeditor/nsHTMLEditor.cpp
+++ b/editor/libeditor/nsHTMLEditor.cpp
@@ -195,7 +195,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsHTMLEditor, nsPlaintextEdito
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMouseMotionListenerP)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mSelectionListenerP)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResizeEventListenerP)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(objectResizeEventListeners)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mObjectResizeEventListeners)
 
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAbsolutelyPositionedObject)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mGrabber)
diff --git a/editor/libeditor/nsHTMLEditor.h b/editor/libeditor/nsHTMLEditor.h
index 99d47abff1f..d6b0636c4a0 100644
--- a/editor/libeditor/nsHTMLEditor.h
+++ b/editor/libeditor/nsHTMLEditor.h
@@ -7,7 +7,6 @@
 #define nsHTMLEditor_h__
 
 #include "nsCOMPtr.h"
-#include "nsCOMArray.h"
 #include "nsPlaintextEditor.h"
 #include "nsIEditor.h"
 #include "nsIHTMLEditor.h"
@@ -850,7 +849,7 @@ protected:
   nsCOMPtr<nsISelectionListener> mSelectionListenerP;
   nsCOMPtr<nsIDOMEventListener>  mResizeEventListenerP;
 
-  nsCOMArray<nsIHTMLObjectResizeListener> objectResizeEventListeners;
+  nsTArray<mozilla::dom::OwningNonNull<nsIHTMLObjectResizeListener>> mObjectResizeEventListeners;
 
   int32_t mOriginalX;
   int32_t mOriginalY;
diff --git a/editor/libeditor/nsHTMLObjectResizer.cpp b/editor/libeditor/nsHTMLObjectResizer.cpp
index 96cca62f4d4..3948aec4d3a 100644
--- a/editor/libeditor/nsHTMLObjectResizer.cpp
+++ b/editor/libeditor/nsHTMLObjectResizer.cpp
@@ -499,14 +499,8 @@ nsresult
 nsHTMLEditor::StartResizing(nsIDOMElement *aHandle)
 {
   // First notify the listeners if any
-  int32_t listenersCount = objectResizeEventListeners.Count();
-  if (listenersCount) {
-    nsCOMPtr<nsIHTMLObjectResizeListener> listener;
-    int32_t index;
-    for (index = 0; index < listenersCount; index++) {
-      listener = objectResizeEventListeners[index];
-      listener->OnStartResizing(static_cast<nsIDOMElement*>(GetAsDOMNode(mResizedObject)));
-    }
+  for (auto& listener : mObjectResizeEventListeners) {
+    listener->OnStartResizing(static_cast<nsIDOMElement*>(GetAsDOMNode(mResizedObject)));
   }
 
   mIsResizing = true;
@@ -976,16 +970,10 @@ nsHTMLEditor::SetFinalSize(int32_t aX, int32_t aY)
                                        EmptyString());
   }
   // finally notify the listeners if any
-  int32_t listenersCount = objectResizeEventListeners.Count();
-  if (listenersCount) {
-    nsCOMPtr<nsIHTMLObjectResizeListener> listener;
-    int32_t index;
-    for (index = 0; index < listenersCount; index++) {
-      listener = objectResizeEventListeners[index];
-      listener->OnEndResizing(static_cast<nsIDOMElement*>(GetAsDOMNode(mResizedObject)),
-                              mResizedObjectWidth, mResizedObjectHeight,
-                              width, height);
-    }
+  for (auto& listener : mObjectResizeEventListeners) {
+    listener->OnEndResizing(static_cast<nsIDOMElement*>(GetAsDOMNode(mResizedObject)),
+                            mResizedObjectWidth, mResizedObjectHeight, width,
+                            height);
   }
 
   // keep track of that size
@@ -1021,14 +1009,13 @@ NS_IMETHODIMP
 nsHTMLEditor::AddObjectResizeEventListener(nsIHTMLObjectResizeListener * aListener)
 {
   NS_ENSURE_ARG_POINTER(aListener);
-  if (objectResizeEventListeners.Count() &&
-      objectResizeEventListeners.IndexOf(aListener) != -1) {
+  if (mObjectResizeEventListeners.Contains(aListener)) {
     /* listener already registered */
     NS_ASSERTION(false,
                  "trying to register an already registered object resize event listener");
     return NS_OK;
   }
-  objectResizeEventListeners.AppendObject(aListener);
+  mObjectResizeEventListeners.AppendElement(*aListener);
   return NS_OK;
 }
 
@@ -1036,14 +1023,13 @@ NS_IMETHODIMP
 nsHTMLEditor::RemoveObjectResizeEventListener(nsIHTMLObjectResizeListener * aListener)
 {
   NS_ENSURE_ARG_POINTER(aListener);
-  if (!objectResizeEventListeners.Count() ||
-      objectResizeEventListeners.IndexOf(aListener) == -1) {
+  if (!mObjectResizeEventListeners.Contains(aListener)) {
     /* listener was not registered */
     NS_ASSERTION(false,
                  "trying to remove an object resize event listener that was not already registered");
     return NS_OK;
   }
-  objectResizeEventListeners.RemoveObject(aListener);
+  mObjectResizeEventListeners.RemoveElement(aListener);
   return NS_OK;
 }