--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -1719,17 +1719,17 @@ EditorBase::ReplaceContainerWithTransact
   }
 
   // Notify our internal selection state listener.
   // Note: An AutoSelectionRestorer object must be created before calling this
   // to initialize mRangeUpdater.
   AutoReplaceContainerSelNotify selStateNotify(mRangeUpdater, &aOldContainer,
                                                newContainer);
   {
-    AutoTransactionsConserveSelection conserveSelection(this);
+    AutoTransactionsConserveSelection conserveSelection(*this);
     // Move all children from the old container to the new container.
     while (aOldContainer.HasChildren()) {
       nsCOMPtr<nsIContent> child = aOldContainer.GetFirstChild();
       if (NS_WARN_IF(!child)) {
         return nullptr;
       }
       nsresult rv = DeleteNodeWithTransaction(*child);
       if (NS_WARN_IF(NS_FAILED(rv))) {
@@ -1848,17 +1848,17 @@ EditorBase::InsertContainerWithTransacti
 
   // Put aNode in the new container, first.
   nsresult rv = DeleteNodeWithTransaction(aContent);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return nullptr;
   }
 
   {
-    AutoTransactionsConserveSelection conserveSelection(this);
+    AutoTransactionsConserveSelection conserveSelection(*this);
     rv = InsertNodeWithTransaction(aContent,
                                    EditorRawDOMPoint(newContainer, 0));
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return nullptr;
     }
   }
 
   // Put the new container where aNode was.
@@ -2648,19 +2648,20 @@ EditorBase::FindBetterInsertionPoint(con
 
 nsresult
 EditorBase::InsertTextWithTransaction(
               nsIDocument& aDocument,
               const nsAString& aStringToInsert,
               const EditorRawDOMPoint& aPointToInsert,
               EditorRawDOMPoint* aPointAfterInsertedString)
 {
-  // NOTE: caller *must* have already used AutoTransactionsConserveSelection
-  // stack-based class to turn off txn selection updating.  Caller also turned
-  // on rules sniffing if desired.
+  MOZ_ASSERT(ShouldHandleIMEComposition() ||
+             !AllowsTransactionsToChangeSelection(),
+             "caller must have already used AutoTransactionsConserveSelection "
+             "if this is not for updating composition string");
 
   if (NS_WARN_IF(!aPointToInsert.IsSet())) {
     return NS_ERROR_INVALID_ARG;
   }
 
   MOZ_ASSERT(aPointToInsert.IsSetAndValid());
 
   if (!ShouldHandleIMEComposition() && aStringToInsert.IsEmpty()) {

--- a/editor/libeditor/EditorUtils.h
+++ b/editor/libeditor/EditorUtils.h
@@ -567,39 +567,34 @@ protected:
 
 /***************************************************************************
  * stack based helper class for turning off active selection adjustment
  * by low level transactions
  */
 class MOZ_RAII AutoTransactionsConserveSelection final
 {
 public:
-  explicit AutoTransactionsConserveSelection(EditorBase* aEditorBase
+  explicit AutoTransactionsConserveSelection(EditorBase& aEditorBase
                                              MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
     : mEditorBase(aEditorBase)
-    , mAllowedTransactionsToChangeSelection(true)
+    , mAllowedTransactionsToChangeSelection(
+        aEditorBase.AllowsTransactionsToChangeSelection())
   {
     MOZ_GUARD_OBJECT_NOTIFIER_INIT;
-    if (mEditorBase) {
-      mAllowedTransactionsToChangeSelection =
-        mEditorBase->AllowsTransactionsToChangeSelection();
-      mEditorBase->MakeThisAllowTransactionsToChangeSelection(false);
-    }
+    mEditorBase.MakeThisAllowTransactionsToChangeSelection(false);
   }
 
   ~AutoTransactionsConserveSelection()
   {
-    if (mEditorBase) {
-      mEditorBase->MakeThisAllowTransactionsToChangeSelection(
-                     mAllowedTransactionsToChangeSelection);
-    }
+    mEditorBase.MakeThisAllowTransactionsToChangeSelection(
+                  mAllowedTransactionsToChangeSelection);
   }
 
 protected:
-  EditorBase* mEditorBase;
+  EditorBase& mEditorBase;
   bool mAllowedTransactionsToChangeSelection;
   MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
 };
 
 /***************************************************************************
  * stack based helper class for batching reflow and paint requests.
  */
 class MOZ_RAII AutoUpdateViewBatch final

--- a/editor/libeditor/HTMLEditRules.cpp
+++ b/editor/libeditor/HTMLEditRules.cpp
@@ -486,17 +486,17 @@ HTMLEditRules::AfterEditInner(EditSubAct
       bDamagedRange = true;
     }
   }
 
   if (bDamagedRange && !((aEditSubAction == EditSubAction::eUndo) ||
                          (aEditSubAction == EditSubAction::eRedo))) {
     // don't let any txns in here move the selection around behind our back.
     // Note that this won't prevent explicit selection setting from working.
-    AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+    AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
 
     // expand the "changed doc range" as needed
     PromoteRange(*mDocChangeRange, aEditSubAction);
 
     // if we did a ranged deletion or handling backspace key, make sure we have
     // a place to put caret.
     // Note we only want to do this if the overall operation was deletion,
     // not if deletion was done along the way for
@@ -1444,17 +1444,17 @@ HTMLEditRules::WillInsertText(EditSubAct
 
   // turn off the edit listener: we know how to
   // build the "doc changed range" ourselves, and it's
   // must faster to do it once here than to track all
   // the changes one at a time.
   AutoLockListener lockit(&mListenerEnabled);
 
   // don't change my selection in subtransactions
-  AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+  AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
   nsAutoString tString(*inString);
   const char16_t *unicodeBuf = tString.get();
   int32_t pos = 0;
   NS_NAMED_LITERAL_STRING(newlineStr, LFSTR);
 
   {
     AutoTrackDOMPoint tracker(HTMLEditorRef().mRangeUpdater, &pointToInsert);
 
@@ -2962,17 +2962,17 @@ HTMLEditRules::WillDeleteSelection(nsIEd
   if (NS_WARN_IF(!endNode)) {
     return NS_ERROR_FAILURE;
   }
   int32_t endOffset = firstRange->EndOffset();
 
   // Figure out if the endpoints are in nodes that can be merged.  Adjust
   // surrounding whitespace in preparation to delete selection.
   if (!IsPlaintextEditor()) {
-    AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+    AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
     rv = WSRunObject::PrepareToDeleteRange(&HTMLEditorRef(),
                                            address_of(startNode), &startOffset,
                                            address_of(endNode), &endOffset);
     if (NS_WARN_IF(!CanHandleEditAction())) {
       return NS_ERROR_EDITOR_DESTROYED;
     }
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
@@ -3378,17 +3378,17 @@ HTMLEditRules::TryToJoinBlocksWithTransa
       MOZ_DIAGNOSTIC_ASSERT(!atChildInBlock.IsSet());
       leftBlock = leftList;
       rightBlock = rightList;
       mergeLists = true;
       existingList = leftList->NodeInfo()->NameAtom();
     }
   }
 
-  AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+  AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
 
   // offset below is where you find yourself in rightBlock when you traverse
   // upwards from leftBlock
   EditorDOMPoint atRightBlockChild;
   if (EditorUtils::IsDescendantOf(*leftBlock, *rightBlock,
                                   &atRightBlockChild)) {
     // Tricky case.  Left block is inside right block.  Do ws adjustment.  This
     // just destroys non-visible ws at boundaries we will be joining.
@@ -4501,17 +4501,17 @@ HTMLEditRules::MakeBasicBlock(nsAtom& bl
   MOZ_ASSERT(IsEditorDataAvailable());
 
   nsresult rv = NormalizeSelection();
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   AutoSelectionRestorer selectionRestorer(&SelectionRef(), &HTMLEditorRef());
-  AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+  AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
 
   // Contruct a list of nodes to act on.
   nsTArray<OwningNonNull<nsINode>> arrayOfNodes;
   rv = GetNodesFromSelection(EditSubAction::eCreateOrRemoveBlock, arrayOfNodes,
                              TouchContent::yes);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
@@ -5916,17 +5916,17 @@ HTMLEditRules::CreateStyleForInsertText(
     return NS_ERROR_FAILURE;
   }
 
   // process clearing any styles first
   UniquePtr<PropItem> item = HTMLEditorRef().mTypeInState->TakeClearProperty();
 
   {
     // Transactions may set selection, but we will set selection if necessary.
-    AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+    AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
 
     while (item && node != rootElement) {
       // XXX If we redesign ClearStyle(), we can use EditorDOMPoint in this
       //     method.
       nsresult rv =
         HTMLEditorRef().ClearStyle(address_of(node), &offset,
                                    item->tag, item->attr);
       if (NS_WARN_IF(!CanHandleEditAction())) {
@@ -7543,17 +7543,17 @@ HTMLEditRules::GetListActionNodes(
     // the selection spans multiple lists but with no common list parent.
     if (!aOutArrayOfNodes.IsEmpty()) {
       return NS_OK;
     }
   }
 
   {
     // We don't like other people messing with our selection!
-    AutoTransactionsConserveSelection dontChangeMySelection(&HTMLEditorRef());
+    AutoTransactionsConserveSelection dontChangeMySelection(HTMLEditorRef());
 
     // contruct a list of nodes to act on.
     nsresult rv = GetNodesFromSelection(EditSubAction::eCreateOrChangeList,
                                         aOutArrayOfNodes, aTouchContent);
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
   }

--- a/editor/libeditor/HTMLEditor.cpp
+++ b/editor/libeditor/HTMLEditor.cpp
@@ -3607,17 +3607,17 @@ HTMLEditor::GetEnclosingTable(nsINode* a
  * "adjacent" means literally adjacent siblings of the same parent.
  * Uses EditorBase::JoinNodesWithTransaction() so action is undoable.
  * Should be called within the context of a batch transaction.
  */
 nsresult
 HTMLEditor::CollapseAdjacentTextNodes(nsRange* aInRange)
 {
   NS_ENSURE_TRUE(aInRange, NS_ERROR_NULL_POINTER);
-  AutoTransactionsConserveSelection dontChangeMySelection(this);
+  AutoTransactionsConserveSelection dontChangeMySelection(*this);
   nsTArray<nsCOMPtr<nsINode>> textNodes;
   // we can't actually do anything during iteration, so store the text nodes in an array
   // don't bother ref counting them because we know we can hold them for the
   // lifetime of this method
 
 
   // build a list of editable text nodes
   nsresult rv = NS_ERROR_UNEXPECTED;
@@ -4271,17 +4271,17 @@ HTMLEditor::SetCSSBackgroundColorWithTra
 
   bool isCollapsed = selection->IsCollapsed();
 
   AutoPlaceholderBatch batchIt(this);
   AutoTopLevelEditSubActionNotifier maybeTopLevelEditSubAction(
                                       *this, EditSubAction::eInsertElement,
                                       nsIEditor::eNext);
   AutoSelectionRestorer selectionRestorer(selection, this);
-  AutoTransactionsConserveSelection dontChangeMySelection(this);
+  AutoTransactionsConserveSelection dontChangeMySelection(*this);
 
   // XXX Although, this method may set background color of ancestor block
   //     element, using EditSubAction::eSetTextProperty.
   bool cancel, handled;
   EditSubActionInfo subActionInfo(EditSubAction::eSetTextProperty);
   nsresult rv =
     rules->WillDoAction(selection, subActionInfo, &cancel, &handled);
   if (NS_WARN_IF(NS_FAILED(rv))) {

--- a/editor/libeditor/HTMLEditorDataTransfer.cpp
+++ b/editor/libeditor/HTMLEditorDataTransfer.cpp
@@ -1106,17 +1106,17 @@ HTMLEditor::InsertFromTransferable(nsITr
   nsresult rv = NS_OK;
   nsAutoCString bestFlavor;
   nsCOMPtr<nsISupports> genericDataObj;
   uint32_t len = 0;
   if (NS_SUCCEEDED(
         transferable->GetAnyTransferData(bestFlavor,
                                          getter_AddRefs(genericDataObj),
                                          &len))) {
-    AutoTransactionsConserveSelection dontChangeMySelection(this);
+    AutoTransactionsConserveSelection dontChangeMySelection(*this);
     nsAutoString flavor;
     CopyASCIItoUTF16(bestFlavor, flavor);
     nsAutoString stuffToPaste;
     bool isSafe = IsSafeToInsertData(aSourceDoc);
 
     if (bestFlavor.EqualsLiteral(kFileMime) ||
         bestFlavor.EqualsLiteral(kJPEGImageMime) ||
         bestFlavor.EqualsLiteral(kJPGImageMime) ||

--- a/editor/libeditor/HTMLStyleEditor.cpp
+++ b/editor/libeditor/HTMLStyleEditor.cpp
@@ -84,17 +84,17 @@ HTMLEditor::SetInlineProperty(nsAtom* aP
     return NS_OK;
   }
 
   AutoPlaceholderBatch batchIt(this);
   AutoTopLevelEditSubActionNotifier maybeTopLevelEditSubAction(
                                       *this, EditSubAction::eInsertElement,
                                       nsIEditor::eNext);
   AutoSelectionRestorer selectionRestorer(selection, this);
-  AutoTransactionsConserveSelection dontChangeMySelection(this);
+  AutoTransactionsConserveSelection dontChangeMySelection(*this);
 
   bool cancel, handled;
   EditSubActionInfo subActionInfo(EditSubAction::eSetTextProperty);
   // Protect the edit rules object from dying
   nsresult rv =
     rules->WillDoAction(selection, subActionInfo, &cancel, &handled);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
@@ -1239,17 +1239,17 @@ HTMLEditor::RemoveInlineProperty(nsAtom*
     return NS_OK;
   }
 
   AutoPlaceholderBatch batchIt(this);
   AutoTopLevelEditSubActionNotifier maybeTopLevelEditSubAction(
                                       *this, EditSubAction::eRemoveTextProperty,
                                       nsIEditor::eNext);
   AutoSelectionRestorer selectionRestorer(selection, this);
-  AutoTransactionsConserveSelection dontChangeMySelection(this);
+  AutoTransactionsConserveSelection dontChangeMySelection(*this);
 
   bool cancel, handled;
   EditSubActionInfo subActionInfo(EditSubAction::eRemoveTextProperty);
   // Protect the edit rules object from dying
   RefPtr<TextEditRules> rules(mRules);
   nsresult rv =
     rules->WillDoAction(selection, subActionInfo, &cancel, &handled);
   if (NS_WARN_IF(NS_FAILED(rv))) {
@@ -1400,17 +1400,17 @@ HTMLEditor::RelativeFontChange(FontSize 
   }
 
   // Wrap with txn batching, rules sniffing, and selection preservation code
   AutoPlaceholderBatch batchIt(this);
   AutoTopLevelEditSubActionNotifier maybeTopLevelEditSubAction(
                                       *this, EditSubAction::eSetTextProperty,
                                       nsIEditor::eNext);
   AutoSelectionRestorer selectionRestorer(selection, this);
-  AutoTransactionsConserveSelection dontChangeMySelection(this);
+  AutoTransactionsConserveSelection dontChangeMySelection(*this);
 
   // Loop through the ranges in the selection
   AutoRangeArray arrayOfRanges(selection);
   for (auto& range : arrayOfRanges.mRanges) {
     // Adjust range to include any ancestors with entirely selected children
     nsresult rv = PromoteInlineRange(*range);
     NS_ENSURE_SUCCESS(rv, rv);
 

--- a/editor/libeditor/HTMLTableEditor.cpp
+++ b/editor/libeditor/HTMLTableEditor.cpp
@@ -134,17 +134,17 @@ HTMLEditor::InsertCell(Element* aCell,
   }
   if (aAfter) {
     DebugOnly<bool> advanced = pointToInsert.AdvanceOffset();
     NS_WARNING_ASSERTION(advanced,
       "Failed to advance offset to after the old cell");
   }
 
   // Don't let Rules System change the selection.
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
   return InsertNodeWithTransaction(*newCell, pointToInsert);
 }
 
 nsresult
 HTMLEditor::SetColSpan(Element* aCell,
                        int32_t aColSpan)
 {
   if (NS_WARN_IF(!aCell)) {
@@ -194,17 +194,17 @@ HTMLEditor::InsertTableCell(int32_t aNum
   NS_ENSURE_SUCCESS(rv, rv);
   NS_ENSURE_TRUE(curCell, NS_ERROR_FAILURE);
   int32_t newCellIndex = aAfter ? (startColIndex+colSpan) : startColIndex;
   //We control selection resetting after the insert...
   AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                              newCellIndex, ePreviousColumn,
                                              false);
   //...so suppress Rules System selection munging
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
   for (int32_t i = 0; i < aNumber; i++) {
     RefPtr<Element> newCell;
     rv = CreateElementWithDefaults(NS_LITERAL_STRING("td"),
                                    getter_AddRefs(newCell));
     if (NS_SUCCEEDED(rv) && newCell) {
       if (aAfter) {
         cellOffset++;
@@ -395,17 +395,17 @@ HTMLEditor::InsertTableColumn(int32_t aN
   rv = GetTableSize(table, &rowCount, &colCount);
   NS_ENSURE_SUCCESS(rv, rv);
 
   //We reset caret in destructor...
   AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                              startColIndex, ePreviousRow,
                                              false);
   //.. so suppress Rules System selection munging
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
   // If we are inserting after all existing columns
   // Make sure table is "well formed"
   //  before appending new column
   if (startColIndex >= colCount) {
     NormalizeTable(table);
   }
 
@@ -527,17 +527,17 @@ HTMLEditor::InsertTableRow(int32_t aNumb
     }
   }
 
   //We control selection resetting after the insert...
   AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                              startColIndex, ePreviousColumn,
                                              false);
   //...so suppress Rules System selection munging
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
   RefPtr<Element> cellForRowParent;
   int32_t cellsInRow = 0;
   if (startRowIndex < rowCount) {
     // We are inserting above an existing row
     // Get each cell in the insert row to adjust for COLSPAN effects while we
     //   count how many cells are needed
     int32_t colIndex = 0;
@@ -744,17 +744,17 @@ HTMLEditor::DeleteTableCell(int32_t aNum
     rv = GetCellIndexes(cell, &startRowIndex, &startColIndex);
     NS_ENSURE_SUCCESS(rv, rv);
 
     // The setCaret object will call AutoSelectionSetterAfterTableEdit in its
     // destructor
     AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                                startColIndex, ePreviousColumn,
                                                false);
-    AutoTransactionsConserveSelection dontChangeSelection(this);
+    AutoTransactionsConserveSelection dontChangeSelection(*this);
 
     bool    checkToDeleteRow = true;
     bool    checkToDeleteColumn = true;
     while (cell) {
       bool deleteRow = false;
       bool deleteCol = false;
 
       if (checkToDeleteRow) {
@@ -873,17 +873,17 @@ HTMLEditor::DeleteTableCell(int32_t aNum
       } else {
         // More than 1 cell in the row
 
         // The setCaret object will call AutoSelectionSetterAfterTableEdit in its
         // destructor
         AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                                    startColIndex, ePreviousColumn,
                                                    false);
-        AutoTransactionsConserveSelection dontChangeSelection(this);
+        AutoTransactionsConserveSelection dontChangeSelection(*this);
         rv = DeleteNodeWithTransaction(*cell);
         // If we fail, don't try to delete any more cells???
         if (NS_WARN_IF(NS_FAILED(rv))) {
           return rv;
         }
       }
     }
   }
@@ -908,17 +908,17 @@ HTMLEditor::DeleteTableCellContents()
 
 
   AutoPlaceholderBatch beginBatching(this);
   // Prevent rules testing until we're done
   AutoTopLevelEditSubActionNotifier maybeTopLevelEditSubAction(
                                       *this, EditSubAction::eDeleteNode,
                                       nsIEditor::eNext);
   //Don't let Rules System change the selection
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
 
   RefPtr<Element> firstCell;
   rv = GetFirstSelectedCell(nullptr, getter_AddRefs(firstCell));
   NS_ENSURE_SUCCESS(rv, rv);
 
 
   if (firstCell) {
@@ -1172,17 +1172,17 @@ HTMLEditor::DeleteTableRow(int32_t aNumb
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   //We control selection resetting after the insert...
   AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                              startColIndex, ePreviousRow,
                                              false);
   // Don't change selection during deletions
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
   if (firstCell && rangeCount > 1) {
     // Use selected cells to determine what rows to delete
     cell = firstCell;
 
     while (cell) {
       if (cell != firstCell) {
         rv = GetCellIndexes(cell, &startRowIndex, &startColIndex);
@@ -1683,17 +1683,17 @@ HTMLEditor::SplitTableCell()
                                       *this, EditSubAction::eInsertNode,
                                       nsIEditor::eNext);
 
   // We reset selection
   AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
                                              startColIndex, ePreviousColumn,
                                              false);
   //...so suppress Rules System selection munging
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
   RefPtr<Element> newCell;
   int32_t rowIndex = startRowIndex;
   int32_t rowSpanBelow, colSpanAfter;
 
   // Split up cell row-wise first into rowspan=1 above, and the rest below,
   //  whittling away at the cell below until no more extra span
   for (rowSpanBelow = actualRowSpan-1; rowSpanBelow >= 0; rowSpanBelow--) {
@@ -1968,17 +1968,17 @@ HTMLEditor::JoinTableCells(bool aMergeNo
                                &startRowIndex, &startColIndex);
   NS_ENSURE_SUCCESS(rv, rv);
   if (!table || !targetCell) {
     return NS_SUCCESS_EDITOR_ELEMENT_NOT_FOUND;
   }
 
   AutoPlaceholderBatch beginBatching(this);
   //Don't let Rules System change the selection
-  AutoTransactionsConserveSelection dontChangeSelection(this);
+  AutoTransactionsConserveSelection dontChangeSelection(*this);
 
   // Note: We dont' use AutoSelectionSetterAfterTableEdit here so the selection
   //  is retained after joining. This leaves the target cell selected
   //  as well as the "non-contiguous" cells, so user can see what happened.
 
   RefPtr<Element> firstCell;
   int32_t firstRowIndex, firstColIndex;
   rv = GetFirstSelectedCellInTable(&firstRowIndex, &firstColIndex,

--- a/editor/libeditor/TextEditRules.cpp
+++ b/editor/libeditor/TextEditRules.cpp
@@ -373,17 +373,17 @@ TextEditRules::DidDoAction(Selection* aS
   if (NS_WARN_IF(!CanHandleEditAction())) {
     return NS_ERROR_EDITOR_DESTROYED;
   }
 
   AutoSafeEditorData setData(*this, *mTextEditor, *aSelection);
 
   // don't let any txns in here move the selection around behind our back.
   // Note that this won't prevent explicit selection setting from working.
-  AutoTransactionsConserveSelection dontChangeMySelection(&TextEditorRef());
+  AutoTransactionsConserveSelection dontChangeMySelection(TextEditorRef());
 
   switch (aInfo.mEditSubAction) {
     case EditSubAction::eDeleteSelectedContent:
       return DidDeleteSelection();
     case EditSubAction::eUndo:
       return DidUndo(aResult);
     case EditSubAction::eRedo:
       return DidRedo(aResult);
@@ -844,17 +844,17 @@ TextEditRules::WillInsertText(EditSubAct
     }
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;
     }
   } else {
     // aEditSubAction == EditSubAction::eInsertText
 
     // don't change my selection in subtransactions
-    AutoTransactionsConserveSelection dontChangeMySelection(&TextEditorRef());
+    AutoTransactionsConserveSelection dontChangeMySelection(TextEditorRef());
 
     EditorRawDOMPoint pointAfterStringInserted;
     rv = TextEditorRef().InsertTextWithTransaction(*doc, *outString,
                                                    atStartOfSelection,
                                                    &pointAfterStringInserted);
     if (NS_WARN_IF(!CanHandleEditAction())) {
       return NS_ERROR_EDITOR_DESTROYED;
     }
@@ -1472,17 +1472,17 @@ TextEditRules::CreateTrailingBRIfNeeded(
 
   nsCOMPtr<nsIContent> lastChild = rootElement->GetLastChild();
   // assuming CreateBogusNodeIfNeeded() has been called first
   if (NS_WARN_IF(!lastChild)) {
     return NS_ERROR_FAILURE;
   }
 
   if (!lastChild->IsHTMLElement(nsGkAtoms::br)) {
-    AutoTransactionsConserveSelection dontChangeMySelection(&TextEditorRef());
+    AutoTransactionsConserveSelection dontChangeMySelection(TextEditorRef());
     EditorRawDOMPoint endOfRoot;
     endOfRoot.SetToEndOf(rootElement);
     CreateElementResult createMozBrResult = CreateMozBR(endOfRoot);
     if (NS_WARN_IF(createMozBrResult.Failed())) {
       return createMozBrResult.Rv();
     }
     return NS_OK;
   }

--- a/editor/libeditor/TextEditor.cpp
+++ b/editor/libeditor/TextEditor.cpp
@@ -1090,17 +1090,17 @@ TextEditor::InsertParagraphSeparatorAsAc
 
     // we need to get the doc
     nsCOMPtr<nsIDocument> doc = GetDocument();
     if (NS_WARN_IF(!doc)) {
       return NS_ERROR_NOT_INITIALIZED;
     }
 
     // don't change my selection in subtransactions
-    AutoTransactionsConserveSelection dontChangeMySelection(this);
+    AutoTransactionsConserveSelection dontChangeMySelection(*this);
 
     // insert a linefeed character
     EditorRawDOMPoint pointAfterInsertedLineBreak;
     rv = InsertTextWithTransaction(*doc, NS_LITERAL_STRING("\n"), pointToInsert,
                                    &pointAfterInsertedLineBreak);
     if (NS_WARN_IF(!pointAfterInsertedLineBreak.IsSet())) {
       rv = NS_ERROR_NULL_POINTER; // don't return here, so DidDoAction is called
     }

--- a/editor/libeditor/TextEditorDataTransfer.cpp
+++ b/editor/libeditor/TextEditorDataTransfer.cpp
@@ -110,17 +110,17 @@ TextEditor::InsertTextFromTransferable(n
   nsCOMPtr<nsISupports> genericDataObj;
   uint32_t len = 0;
   if (NS_SUCCEEDED(
         aTransferable->GetAnyTransferData(bestFlavor,
                                           getter_AddRefs(genericDataObj),
                                           &len)) &&
       (bestFlavor.EqualsLiteral(kUnicodeMime) ||
        bestFlavor.EqualsLiteral(kMozTextInternal))) {
-    AutoTransactionsConserveSelection dontChangeMySelection(this);
+    AutoTransactionsConserveSelection dontChangeMySelection(*this);
     nsCOMPtr<nsISupportsString> textDataObj ( do_QueryInterface(genericDataObj) );
     if (textDataObj && len > 0) {
       nsAutoString stuffToPaste;
       textDataObj->GetData(stuffToPaste);
       NS_ASSERTION(stuffToPaste.Length() <= (len/2), "Invalid length!");
 
       // Sanitize possible carriage returns in the string to be inserted
       nsContentUtils::PlatformToDOMLineBreaks(stuffToPaste);

--- a/editor/libeditor/WSRunObject.cpp
+++ b/editor/libeditor/WSRunObject.cpp
@@ -1542,22 +1542,27 @@ nsresult
 WSRunObject::InsertNBSPAndRemoveFollowingASCIIWhitespaces(WSPoint aPoint)
 {
   // MOOSE: this routine needs to be modified to preserve the integrity of the
   // wsFragment info.
   if (NS_WARN_IF(!aPoint.mTextNode)) {
     return NS_ERROR_NULL_POINTER;
   }
 
- // First, insert an NBSP.
-  AutoTransactionsConserveSelection dontChangeMySelection(mHTMLEditor);
+  if (NS_WARN_IF(!mHTMLEditor)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  RefPtr<HTMLEditor> htmlEditor(mHTMLEditor);
+
+  // First, insert an NBSP.
+  AutoTransactionsConserveSelection dontChangeMySelection(*htmlEditor);
   nsresult rv =
-    mHTMLEditor->InsertTextIntoTextNodeWithTransaction(
-                   nsDependentSubstring(&kNBSP, 1),
-                   *aPoint.mTextNode, aPoint.mOffset, true);
+    htmlEditor->InsertTextIntoTextNodeWithTransaction(
+                  nsDependentSubstring(&kNBSP, 1),
+                  *aPoint.mTextNode, aPoint.mOffset, true);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   // Now, the text node may have been modified by mutation observer.
   // So, the NBSP may have gone.
   if (aPoint.mTextNode->TextDataLength() <= aPoint.mOffset ||
       aPoint.mTextNode->GetText()->CharAt(aPoint.mOffset) != kNBSP) {
@@ -1886,24 +1891,26 @@ WSRunObject::CheckTrailingNBSPOfRun(WSFr
         // Refresh thePoint, prevPoint
         thePoint = GetPreviousCharPoint(aRun->EndPoint());
         prevPoint = GetPreviousCharPoint(thePoint);
         rightCheck = true;
       }
     }
     if (leftCheck && rightCheck) {
       // Now replace nbsp with space.  First, insert a space
-      AutoTransactionsConserveSelection dontChangeMySelection(htmlEditor);
+      AutoTransactionsConserveSelection dontChangeMySelection(*htmlEditor);
       nsAutoString spaceStr(char16_t(32));
       nsresult rv =
         htmlEditor->InsertTextIntoTextNodeWithTransaction(spaceStr,
                                                           *thePoint.mTextNode,
                                                           thePoint.mOffset,
                                                           true);
-      NS_ENSURE_SUCCESS(rv, rv);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
 
       // Finally, delete that nbsp
       rv = DeleteRange(EditorRawDOMPoint(thePoint.mTextNode,
                                          thePoint.mOffset + 1),
                        EditorRawDOMPoint(thePoint.mTextNode,
                                          thePoint.mOffset + 2));
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
@@ -1928,22 +1935,24 @@ WSRunObject::CheckTrailingNBSPOfRun(WSFr
                                                   thePoint.mOffset),
                                 EditorRawDOMPoint(thePoint.mTextNode,
                                                   thePoint.mOffset + 1));
       if (NS_WARN_IF(NS_FAILED(rv))) {
         return rv;
       }
 
       // Finally, insert that nbsp before the ASCII ws run
-      AutoTransactionsConserveSelection dontChangeMySelection(htmlEditor);
+      AutoTransactionsConserveSelection dontChangeMySelection(*htmlEditor);
       rv =
         htmlEditor->InsertTextIntoTextNodeWithTransaction(
                       nsDependentSubstring(&kNBSP, 1),
                       *startNode, startOffset, true);
-      NS_ENSURE_SUCCESS(rv, rv);
+      if (NS_WARN_IF(NS_FAILED(rv))) {
+        return rv;
+      }
     }
   }
   return NS_OK;
 }
 
 template<typename PT, typename CT>
 nsresult
 WSRunObject::ReplacePreviousNBSPIfUnncessary(
@@ -1980,23 +1989,28 @@ WSRunObject::ReplacePreviousNBSPIfUnnces
       canConvert = true;
     }
   }
 
   if (!canConvert) {
     return NS_OK;
   }
 
+  if (NS_WARN_IF(!mHTMLEditor)) {
+    return NS_ERROR_NOT_INITIALIZED;
+  }
+  RefPtr<HTMLEditor> htmlEditor(mHTMLEditor);
+
   // First, insert a space before the previous NBSP.
-  AutoTransactionsConserveSelection dontChangeMySelection(mHTMLEditor);
+  AutoTransactionsConserveSelection dontChangeMySelection(*htmlEditor);
   nsAutoString spaceStr(char16_t(32));
   nsresult rv =
-    mHTMLEditor->InsertTextIntoTextNodeWithTransaction(spaceStr,
-                                                       *thePoint.mTextNode,
-                                                       thePoint.mOffset, true);
+    htmlEditor->InsertTextIntoTextNodeWithTransaction(spaceStr,
+                                                      *thePoint.mTextNode,
+                                                      thePoint.mOffset, true);
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
 
   // Finally, delete the previous NBSP.
   rv = DeleteRange(EditorRawDOMPoint(thePoint.mTextNode,
                                      thePoint.mOffset + 1),
                    EditorRawDOMPoint(thePoint.mTextNode,
@@ -2029,25 +2043,32 @@ WSRunObject::CheckLeadingNBSP(WSFragment
       }
     } else if (aRun->mRightType == WSType::text ||
                aRun->mRightType == WSType::special ||
                aRun->mRightType == WSType::br) {
       canConvert = true;
     }
   }
   if (canConvert) {
+    if (NS_WARN_IF(!mHTMLEditor)) {
+      return NS_ERROR_NOT_INITIALIZED;
+    }
+    RefPtr<HTMLEditor> htmlEditor(mHTMLEditor);
+
     // First, insert a space
-    AutoTransactionsConserveSelection dontChangeMySelection(mHTMLEditor);
+    AutoTransactionsConserveSelection dontChangeMySelection(*htmlEditor);
     nsAutoString spaceStr(char16_t(32));
     nsresult rv =
-      mHTMLEditor->InsertTextIntoTextNodeWithTransaction(spaceStr,
-                                                         *thePoint.mTextNode,
-                                                         thePoint.mOffset,
-                                                         true);
-    NS_ENSURE_SUCCESS(rv, rv);
+      htmlEditor->InsertTextIntoTextNodeWithTransaction(spaceStr,
+                                                        *thePoint.mTextNode,
+                                                        thePoint.mOffset,
+                                                        true);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
 
     // Finally, delete that nbsp
     rv = DeleteRange(EditorRawDOMPoint(thePoint.mTextNode,
                                        thePoint.mOffset + 1),
                      EditorRawDOMPoint(thePoint.mTextNode,
                                        thePoint.mOffset + 2));
     if (NS_WARN_IF(NS_FAILED(rv))) {
       return rv;