--- a/editor/libeditor/nsHTMLEditRules.cpp
+++ b/editor/libeditor/nsHTMLEditRules.cpp
@@ -8,16 +8,17 @@
 
 #include <stdlib.h>
 
 #include "mozilla/Assertions.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/dom/Selection.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/OwningNonNull.h"
 #include "mozilla/mozalloc.h"
 #include "nsAString.h"
 #include "nsAlgorithm.h"
 #include "nsCOMArray.h"
 #include "nsCRT.h"
 #include "nsCRTGlue.h"
 #include "nsComponentManagerUtils.h"
 #include "nsContentUtils.h"
@@ -5153,54 +5154,68 @@ nsHTMLEditRules::CheckForInvisibleBR(nsI
       *outBRNode = GetAsDOMNode(wsTester.mStartReasonNode);
     }
   }
 
   return NS_OK;
 }
 
 
-///////////////////////////////////////////////////////////////////////////
-// GetInnerContent: aList and aTbl allow the caller to specify what kind 
-//                  of content to "look inside".  If aTbl is true, look inside
-//                  any table content, and insert the inner content into the
-//                  supplied issupportsarray at offset aIndex.  
-//                  Similarly with aList and list content.
-//                  aIndex is updated to point past inserted elements.
-//                  
+////////////////////////////////////////////////////////////////////////////////
+// GetInnerContent: aList and aTbl allow the caller to specify what kind of
+//                  content to "look inside".  If aTbl is true, look inside any
+//                  table content, and insert the inner content into the
+//                  supplied issupportsarray at offset aIndex.  Similarly with
+//                  aList and list content.  aIndex is updated to point past
+//                  inserted elements.
+//
 nsresult
-nsHTMLEditRules::GetInnerContent(nsIDOMNode *aNode, nsCOMArray<nsIDOMNode> &outArrayOfNodes, 
-                                 int32_t *aIndex, bool aList, bool aTbl)
-{
-  nsCOMPtr<nsINode> aNode_ = do_QueryInterface(aNode);
-  NS_ENSURE_TRUE(aNode_ && aIndex, NS_ERROR_NULL_POINTER);
-
-  nsCOMPtr<nsIDOMNode> node =
-    GetAsDOMNode(mHTMLEditor->GetFirstEditableChild(*aNode_));
-  nsresult res = NS_OK;
-  while (NS_SUCCEEDED(res) && node)
-  {
-    if (  ( aList && (nsHTMLEditUtils::IsList(node)     || 
-                      nsHTMLEditUtils::IsListItem(node) ) )
-       || ( aTbl && nsHTMLEditUtils::IsTableElement(node) )  )
-    {
-      res = GetInnerContent(node, outArrayOfNodes, aIndex, aList, aTbl);
-      NS_ENSURE_SUCCESS(res, res);
-    }
-    else
-    {
-      outArrayOfNodes.InsertObjectAt(node, *aIndex);
+nsHTMLEditRules::GetInnerContent(nsIDOMNode* aNode,
+                                 nsCOMArray<nsIDOMNode>& aOutArrayOfDOMNodes,
+                                 int32_t* aIndex, bool aLists, bool aTables)
+{
+  // To be removed in a subsequent patch
+  nsCOMPtr<nsINode> node = do_QueryInterface(aNode);
+  NS_ENSURE_STATE(node);
+  nsTArray<nsCOMPtr<nsINode>> aOutArrayOfNodes;
+  for (int32_t i = 0; i < aOutArrayOfDOMNodes.Count(); i++) {
+    nsCOMPtr<nsINode> newNode = do_QueryInterface(aOutArrayOfDOMNodes[i]);
+    if (newNode) {
+      aOutArrayOfNodes.AppendElement(newNode);
+    }
+  }
+  GetInnerContent(*node, aOutArrayOfNodes, aIndex,
+                  aLists ? Lists::yes : Lists::no,
+                  aTables ? Tables::yes : Tables::no);
+  aOutArrayOfDOMNodes.Clear();
+  for (auto& node : aOutArrayOfNodes) {
+    aOutArrayOfDOMNodes.AppendElement(GetAsDOMNode(node));
+  }
+
+  return NS_OK;
+}
+
+void
+nsHTMLEditRules::GetInnerContent(nsINode& aNode,
+                                 nsTArray<nsCOMPtr<nsINode>>& aOutArrayOfNodes,
+                                 int32_t* aIndex, Lists aLists, Tables aTables)
+{
+  MOZ_ASSERT(aIndex);
+
+  for (nsCOMPtr<nsIContent> node = mHTMLEditor->GetFirstEditableChild(aNode);
+       node; node = node->GetNextSibling()) {
+    if ((aLists == Lists::yes && (nsHTMLEditUtils::IsList(node) ||
+                                  nsHTMLEditUtils::IsListItem(node))) ||
+        (aTables == Tables::yes && nsHTMLEditUtils::IsTableElement(node))) {
+      GetInnerContent(*node, aOutArrayOfNodes, aIndex, aLists, aTables);
+    } else {
+      aOutArrayOfNodes.InsertElementAt(*aIndex, node);
       (*aIndex)++;
     }
-    nsCOMPtr<nsIDOMNode> tmp;
-    res = node->GetNextSibling(getter_AddRefs(tmp));
-    node = tmp;
-  }
-
-  return res;
+  }
 }
 
 ///////////////////////////////////////////////////////////////////////////
 // ExpandSelectionForDeletion: this promotes our selection to include blocks
 // that have all their children selected.
 //                  
 nsresult
 nsHTMLEditRules::ExpandSelectionForDeletion(Selection* aSelection)

--- a/editor/libeditor/nsHTMLEditRules.h
+++ b/editor/libeditor/nsHTMLEditRules.h
@@ -193,17 +193,26 @@ protected:
   nsresult DidAbsolutePosition();
   nsresult AlignInnerBlocks(nsIDOMNode *aNode, const nsAString *alignType);
   nsresult AlignBlockContents(nsIDOMNode *aNode, const nsAString *alignType);
   nsresult AppendInnerFormatNodes(nsCOMArray<nsIDOMNode>& aArray,
                                   nsINode* aNode);
   nsresult AppendInnerFormatNodes(nsCOMArray<nsIDOMNode>& aArray,
                                   nsIDOMNode *aNode);
   nsresult GetFormatString(nsIDOMNode *aNode, nsAString &outFormat);
-  nsresult GetInnerContent(nsIDOMNode *aNode, nsCOMArray<nsIDOMNode>& outArrayOfNodes, int32_t *aIndex, bool aList = true, bool aTble = true);
+  enum class Lists { no, yes };
+  enum class Tables { no, yes };
+  nsresult GetInnerContent(nsIDOMNode* aNode,
+                           nsCOMArray<nsIDOMNode>& aOutArrayOfNodes,
+                           int32_t* aIndex, bool aLists = true,
+                           bool aTables = true);
+  void GetInnerContent(nsINode& aNode,
+                       nsTArray<nsCOMPtr<nsINode>>& aOutArrayOfNodes,
+                       int32_t* aIndex, Lists aLists = Lists::yes,
+                       Tables aTables = Tables::yes);
   already_AddRefed<nsIDOMNode> IsInListItem(nsIDOMNode* aNode);
   mozilla::dom::Element* IsInListItem(nsINode* aNode);
   nsresult ReturnInHeader(mozilla::dom::Selection* aSelection,
                           nsIDOMNode* aHeader, nsIDOMNode* aTextNode,
                           int32_t aOffset);
   nsresult ReturnInParagraph(mozilla::dom::Selection* aSelection,
                              nsIDOMNode* aHeader, nsIDOMNode* aTextNode,
                              int32_t aOffset, bool* aCancel, bool* aHandled);