--- a/editor/composer/nsEditorSpellCheck.cpp
+++ b/editor/composer/nsEditorSpellCheck.cpp
@@ -355,22 +355,17 @@ nsEditorSpellCheck::InitSpellChecker(nsI
 
     nsCOMPtr<nsISelection> domSelection;
     aEditor->GetSelection(getter_AddRefs(domSelection));
     if (NS_WARN_IF(!domSelection)) {
       return NS_ERROR_FAILURE;
     }
     RefPtr<Selection> selection = domSelection->AsSelection();
 
-    int32_t count = 0;
-
-    rv = selection->GetRangeCount(&count);
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    if (count > 0) {
+    if (selection->RangeCount()) {
       RefPtr<nsRange> range = selection->GetRangeAt(0);
       NS_ENSURE_STATE(range);
 
       bool collapsed = false;
       rv = range->GetCollapsed(&collapsed);
       NS_ENSURE_SUCCESS(rv, rv);
 
       if (!collapsed) {

--- a/editor/libeditor/EditorBase.cpp
+++ b/editor/libeditor/EditorBase.cpp
@@ -4899,19 +4899,17 @@ EditorBase::InitializeSelection(nsIDOMEv
   if (selectionRootContent->GetParent()) {
     selection->SetAncestorLimiter(selectionRootContent);
   } else {
     selection->SetAncestorLimiter(nullptr);
   }
 
   // XXX What case needs this?
   if (isTargetDoc) {
-    int32_t rangeCount;
-    selection->GetRangeCount(&rangeCount);
-    if (!rangeCount) {
+    if (!selection->RangeCount()) {
       BeginningOfDocument();
     }
   }
 
   // If there is composition when this is called, we may need to restore IME
   // selection because if the editor is reframed, this already forgot IME
   // selection and the transaction.
   if (mComposition && !mIMETextNode && mIMETextLength) {

--- a/editor/libeditor/EditorEventListener.cpp
+++ b/editor/libeditor/EditorEventListener.cpp
@@ -1018,21 +1018,18 @@ EditorEventListener::CanDrop(nsIDOMDragE
   if (NS_FAILED(rv) || !parent) {
     return false;
   }
 
   int32_t offset = 0;
   rv = aEvent->GetRangeOffset(&offset);
   NS_ENSURE_SUCCESS(rv, false);
 
-  int32_t rangeCount;
-  rv = selection->GetRangeCount(&rangeCount);
-  NS_ENSURE_SUCCESS(rv, false);
-
-  for (int32_t i = 0; i < rangeCount; i++) {
+  uint32_t rangeCount = selection->RangeCount();
+  for (uint32_t i = 0; i < rangeCount; i++) {
     RefPtr<nsRange> range = selection->GetRangeAt(i);
     if (!range) {
       // Don't bail yet, iterate through them all
       continue;
     }
 
     bool inRange = true;
     range->IsPointInRange(parent, offset, &inRange);

--- a/editor/libeditor/HTMLEditRules.cpp
+++ b/editor/libeditor/HTMLEditRules.cpp
@@ -5307,32 +5307,28 @@ HTMLEditRules::NormalizeSelection(Select
 {
   NS_ENSURE_TRUE(inSelection, NS_ERROR_NULL_POINTER);
 
   // don't need to touch collapsed selections
   if (inSelection->Collapsed()) {
     return NS_OK;
   }
 
-  int32_t rangeCount;
-  nsresult rv = inSelection->GetRangeCount(&rangeCount);
-  NS_ENSURE_SUCCESS(rv, rv);
-
   // we don't need to mess with cell selections, and we assume multirange selections are those.
-  if (rangeCount != 1) {
+  if (inSelection->RangeCount() != 1) {
     return NS_OK;
   }
 
   RefPtr<nsRange> range = inSelection->GetRangeAt(0);
   NS_ENSURE_TRUE(range, NS_ERROR_NULL_POINTER);
   nsCOMPtr<nsIDOMNode> startNode, endNode;
   uint32_t startOffset, endOffset;
   nsCOMPtr<nsIDOMNode> newStartNode, newEndNode;
 
-  rv = range->GetStartContainer(getter_AddRefs(startNode));
+  nsresult rv = range->GetStartContainer(getter_AddRefs(startNode));
   NS_ENSURE_SUCCESS(rv, rv);
   rv = range->GetStartOffset(&startOffset);
   NS_ENSURE_SUCCESS(rv, rv);
   rv = range->GetEndContainer(getter_AddRefs(endNode));
   NS_ENSURE_SUCCESS(rv, rv);
   rv = range->GetEndOffset(&endOffset);
   NS_ENSURE_SUCCESS(rv, rv);
 

--- a/editor/libeditor/HTMLEditorEventListener.cpp
+++ b/editor/libeditor/HTMLEditorEventListener.cpp
@@ -126,21 +126,19 @@ HTMLEditorEventListener::MouseDown(nsIDO
 
     int32_t offset = 0;
     rv = aMouseEvent->GetRangeOffset(&offset);
     NS_ENSURE_SUCCESS(rv, rv);
 
     // Detect if mouse point is within current selection for context click
     bool nodeIsInSelection = false;
     if (isContextClick && !selection->Collapsed()) {
-      int32_t rangeCount;
-      rv = selection->GetRangeCount(&rangeCount);
-      NS_ENSURE_SUCCESS(rv, rv);
+      uint32_t rangeCount = selection->RangeCount();
 
-      for (int32_t i = 0; i < rangeCount; i++) {
+      for (uint32_t i = 0; i < rangeCount; i++) {
         RefPtr<nsRange> range = selection->GetRangeAt(i);
         if (!range) {
           // Don't bail yet, iterate through them all
           continue;
         }
 
         range->IsPointInRange(parent, offset, &nodeIsInSelection);
 

--- a/editor/libeditor/HTMLTableEditor.cpp
+++ b/editor/libeditor/HTMLTableEditor.cpp
@@ -759,21 +759,17 @@ HTMLEditor::DeleteTableCell(int32_t aNum
   // Prevent rules testing until we're done
   AutoRules beginRulesSniffing(this, EditAction::deleteNode, nsIEditor::eNext);
 
   nsCOMPtr<nsIDOMElement> firstCell;
   nsCOMPtr<nsIDOMRange> range;
   rv = GetFirstSelectedCell(getter_AddRefs(range), getter_AddRefs(firstCell));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  int32_t rangeCount;
-  rv = selection->GetRangeCount(&rangeCount);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  if (firstCell && rangeCount > 1) {
+  if (firstCell && selection->RangeCount() > 1) {
     // When > 1 selected cell,
     //  ignore aNumber and use selected cells
     cell = firstCell;
 
     int32_t rowCount, colCount;
     rv = GetTableSize(table, &rowCount, &colCount);
     NS_ENSURE_SUCCESS(rv, rv);
 
@@ -1033,19 +1029,17 @@ HTMLEditor::DeleteTableColumn(int32_t aN
   AutoRules beginRulesSniffing(this, EditAction::deleteNode, nsIEditor::eNext);
 
   // Test if deletion is controlled by selected cells
   nsCOMPtr<nsIDOMElement> firstCell;
   nsCOMPtr<nsIDOMRange> range;
   rv = GetFirstSelectedCell(getter_AddRefs(range), getter_AddRefs(firstCell));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  int32_t rangeCount;
-  rv = selection->GetRangeCount(&rangeCount);
-  NS_ENSURE_SUCCESS(rv, rv);
+  uint32_t rangeCount = selection->RangeCount();
 
   if (firstCell && rangeCount > 1) {
     // Fetch indexes again - may be different for selected cells
     rv = GetCellIndexes(firstCell, &startRowIndex, &startColIndex);
     NS_ENSURE_SUCCESS(rv, rv);
   }
   //We control selection resetting after the insert...
   AutoSelectionSetterAfterTableEdit setCaret(*this, table, startRowIndex,
@@ -1198,19 +1192,17 @@ HTMLEditor::DeleteTableRow(int32_t aNumb
   // Prevent rules testing until we're done
   AutoRules beginRulesSniffing(this, EditAction::deleteNode, nsIEditor::eNext);
 
   nsCOMPtr<nsIDOMElement> firstCell;
   nsCOMPtr<nsIDOMRange> range;
   rv = GetFirstSelectedCell(getter_AddRefs(range), getter_AddRefs(firstCell));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  int32_t rangeCount;
-  rv = selection->GetRangeCount(&rangeCount);
-  NS_ENSURE_SUCCESS(rv, rv);
+  uint32_t rangeCount = selection->RangeCount();
 
   if (firstCell && rangeCount > 1) {
     // Fetch indexes again - may be different for selected cells
     rv = GetCellIndexes(firstCell, &startRowIndex, &startColIndex);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   //We control selection resetting after the insert...
@@ -2211,22 +2203,20 @@ HTMLEditor::JoinTableCells(bool aMergeNo
         rv = DeleteNode(node);
         NS_ENSURE_SUCCESS(rv, rv);
       }
     }
     // Cleanup selection: remove ranges where cells were deleted
     RefPtr<Selection> selection = GetSelection();
     NS_ENSURE_TRUE(selection, NS_ERROR_FAILURE);
 
-    int32_t rangeCount;
-    rv = selection->GetRangeCount(&rangeCount);
-    NS_ENSURE_SUCCESS(rv, rv);
+    uint32_t rangeCount = selection->RangeCount();
 
     RefPtr<nsRange> range;
-    for (int32_t i = 0; i < rangeCount; i++) {
+    for (uint32_t i = 0; i < rangeCount; i++) {
       range = selection->GetRangeAt(i);
       NS_ENSURE_TRUE(range, NS_ERROR_FAILURE);
 
       nsCOMPtr<nsIDOMElement> deletedCell;
       GetCellFromRange(range, getter_AddRefs(deletedCell));
       if (!deletedCell) {
         selection->RemoveRange(range);
         rangeCount--;
@@ -3203,18 +3193,17 @@ HTMLEditor::GetSelectedOrParentTableElem
                                      getter_AddRefs(tableOrCellElement));
   NS_ENSURE_SUCCESS(rv, rv);
 
   NS_NAMED_LITERAL_STRING(tdName, "td");
 
   if (tableOrCellElement) {
       // Each cell is in its own selection range,
       //  so count signals multiple-cell selection
-      rv = selection->GetRangeCount(aSelectedCount);
-      NS_ENSURE_SUCCESS(rv, rv);
+      *aSelectedCount = selection->RangeCount();
       aTagName = tdName;
   } else {
     nsCOMPtr<nsIDOMNode> anchorNode;
     rv = selection->GetAnchorNode(getter_AddRefs(anchorNode));
     if (NS_FAILED(rv)) {
       return rv;
     }
     NS_ENSURE_TRUE(anchorNode, NS_ERROR_FAILURE);
@@ -3237,18 +3226,17 @@ HTMLEditor::GetSelectedOrParentTableElem
       } else {
         nsCOMPtr<nsIAtom> atom = EditorBase::GetTag(selectedNode);
 
         if (atom == nsGkAtoms::td) {
           tableOrCellElement = do_QueryInterface(selectedNode);
           aTagName = tdName;
           // Each cell is in its own selection range,
           //  so count signals multiple-cell selection
-          rv = selection->GetRangeCount(aSelectedCount);
-          NS_ENSURE_SUCCESS(rv, rv);
+          *aSelectedCount = selection->RangeCount();
         } else if (atom == nsGkAtoms::table) {
           tableOrCellElement = do_QueryInterface(selectedNode);
           aTagName.AssignLiteral("table");
           *aSelectedCount = 1;
         } else if (atom == nsGkAtoms::tr) {
           tableOrCellElement = do_QueryInterface(selectedNode);
           aTagName.AssignLiteral("tr");
           *aSelectedCount = 1;

--- a/editor/libeditor/TextEditRules.cpp
+++ b/editor/libeditor/TextEditRules.cpp
@@ -127,20 +127,17 @@ TextEditRules::Init(TextEditor* aTextEdi
 
   // Put in a magic br if needed. This method handles null selection,
   // which should never happen anyway
   nsresult rv = CreateBogusNodeIfNeeded(selection);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // If the selection hasn't been set up yet, set it up collapsed to the end of
   // our editable content.
-  int32_t rangeCount;
-  rv = selection->GetRangeCount(&rangeCount);
-  NS_ENSURE_SUCCESS(rv, rv);
-  if (!rangeCount) {
+  if (!selection->RangeCount()) {
     rv = mTextEditor->CollapseSelectionToEnd(selection);
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
   if (IsPlaintextEditor()) {
     // ensure trailing br node
     rv = CreateTrailingBRIfNeeded();
     NS_ENSURE_SUCCESS(rv, rv);

--- a/editor/libeditor/TextEditorDataTransfer.cpp
+++ b/editor/libeditor/TextEditorDataTransfer.cpp
@@ -231,21 +231,19 @@ TextEditor::InsertFromDrop(nsIDOMEvent* 
 
   // Check if mouse is in the selection
   // if so, jump through some hoops to determine if mouse is over selection (bail)
   // and whether user wants to copy selection or delete it
   if (!isCollapsed) {
     // We never have to delete if selection is already collapsed
     bool cursorIsInSelection = false;
 
-    int32_t rangeCount;
-    rv = selection->GetRangeCount(&rangeCount);
-    NS_ENSURE_SUCCESS(rv, rv);
+    uint32_t rangeCount = selection->RangeCount();
 
-    for (int32_t j = 0; j < rangeCount; j++) {
+    for (uint32_t j = 0; j < rangeCount; j++) {
       RefPtr<nsRange> range = selection->GetRangeAt(j);
       if (!range) {
         // don't bail yet, iterate through them all
         continue;
       }
 
       rv = range->IsPointInRange(newSelectionParent, newSelectionOffset, &cursorIsInSelection);
       if (cursorIsInSelection) {

--- a/editor/txtsvc/nsTextServicesDocument.cpp
+++ b/editor/txtsvc/nsTextServicesDocument.cpp
@@ -686,24 +686,17 @@ nsTextServicesDocument::LastSelectedBloc
   }
 
   // If we get here, we have an uncollapsed selection!
   // Look backwards through each range in the selection till you
   // find the first text node. If you find one, find the
   // beginning of its text block, and make it the current
   // block.
 
-  int32_t rangeCount;
-  rv = selection->GetRangeCount(&rangeCount);
-
-  if (NS_FAILED(rv)) {
-    UNLOCK_DOC(this);
-    return rv;
-  }
-
+  int32_t rangeCount = static_cast<int32_t>(selection->RangeCount());
   NS_ASSERTION(rangeCount > 0, "Unexpected range count!");
 
   if (rangeCount <= 0) {
     UNLOCK_DOC(this);
     return NS_OK;
   }
 
   // XXX: We may need to add some code here to make sure
@@ -2565,17 +2558,17 @@ nsTextServicesDocument::GetUncollapsedSe
   RefPtr<Selection> selection = domSelection->AsSelection();
 
   // It is assumed that the calling function has made sure that the
   // selection is not collapsed, and that the input params to this
   // method are initialized to some defaults.
 
   nsCOMPtr<nsIDOMNode> startContainer, endContainer;
   int32_t startOffset, endOffset;
-  int32_t rangeCount, tableCount;
+  int32_t tableCount;
   int32_t e1s1 = 0, e1s2 = 0, e2s1 = 0, e2s2 = 0;
 
   OffsetEntry *eStart, *eEnd;
   int32_t eStartOffset, eEndOffset;
 
   tableCount = mOffsetTable.Length();
 
   // Get pointers to the first and last offset entries
@@ -2587,24 +2580,22 @@ nsTextServicesDocument::GetUncollapsedSe
     eEnd = mOffsetTable[tableCount - 1];
   } else {
     eEnd = eStart;
   }
 
   eStartOffset = eStart->mNodeOffset;
   eEndOffset   = eEnd->mNodeOffset + eEnd->mLength;
 
-  rv = selection->GetRangeCount(&rangeCount);
-
-  NS_ENSURE_SUCCESS(rv, rv);
+  uint32_t rangeCount = selection->RangeCount();
 
   // Find the first range in the selection that intersects
   // the current text block.
 
-  for (int32_t i = 0; i < rangeCount; i++) {
+  for (uint32_t i = 0; i < rangeCount; i++) {
     range = selection->GetRangeAt(i);
     NS_ENSURE_STATE(range);
 
     rv = GetRangeEndPoints(range,
                            getter_AddRefs(startContainer), &startOffset,
                            getter_AddRefs(endContainer), &endOffset);
 
     NS_ENSURE_SUCCESS(rv, rv);