diff --git a/accessible/base/nsCoreUtils.cpp b/accessible/base/nsCoreUtils.cpp
index 095fb6597bd1..8d9782f4f36e 100644
--- a/accessible/base/nsCoreUtils.cpp
+++ b/accessible/base/nsCoreUtils.cpp
@@ -66,8 +66,7 @@ bool nsCoreUtils::HasClickListener(nsIContent *aContent) {
 void nsCoreUtils::DispatchClickEvent(XULTreeElement *aTree,
                                      int32_t aRowIndex, nsTreeColumn *aColumn,
                                      const nsAString &aPseudoElt) {
-  RefPtr<dom::Element> tcElm;
-  aTree->GetTreeBody(getter_AddRefs(tcElm));
+  RefPtr<dom::Element> tcElm = aTree->GetTreeBody();
   if (!tcElm) return;
 
   Document *document = tcElm->GetUncomposedDoc();
@@ -80,10 +79,12 @@ void nsCoreUtils::DispatchClickEvent(XULTreeElement *aTree,
   aTree->EnsureRowIsVisible(aRowIndex);
 
   // Calculate x and y coordinates.
-  int32_t x = 0, y = 0, width = 0, height = 0;
-  nsresult rv = aTree->GetCoordsForCellItem(aRowIndex, aColumn, aPseudoElt, &x,
-                                            &y, &width, &height);
-  if (NS_FAILED(rv)) return;
+  nsresult rv;
+  nsIntRect rect =
+      aTree->GetCoordsForCellItem(aRowIndex, aColumn, aPseudoElt, rv);
+  if (NS_FAILED(rv)) {
+    return;
+  }
 
   nsCOMPtr<nsIBoxObject> tcBoxObj =
       nsXULElement::FromNode(tcElm)->GetBoxObject(IgnoreErrors());
@@ -103,9 +104,9 @@ void nsCoreUtils::DispatchClickEvent(XULTreeElement *aTree,
 
   RefPtr<nsPresContext> presContext = presShell->GetPresContext();
 
-  int32_t cnvdX = presContext->CSSPixelsToDevPixels(tcX + x + 1) +
+  int32_t cnvdX = presContext->CSSPixelsToDevPixels(tcX + int32_t(rect.x) + 1) +
                   presContext->AppUnitsToDevPixels(offset.x);
-  int32_t cnvdY = presContext->CSSPixelsToDevPixels(tcY + y + 1) +
+  int32_t cnvdY = presContext->CSSPixelsToDevPixels(tcY + int32_t(rect.y) + 1) +
                   presContext->AppUnitsToDevPixels(offset.y);
 
   // XUL is just desktop, so there is no real reason for senfing touch events.
@@ -426,8 +427,7 @@ void nsCoreUtils::GetLanguageFor(nsIContent *aContent, nsIContent *aRootContent,
 
 already_AddRefed<nsIBoxObject> nsCoreUtils::GetTreeBodyBoxObject(
     XULTreeElement *aTree) {
-  RefPtr<dom::Element> tcElm;
-  aTree->GetTreeBody(getter_AddRefs(tcElm));
+  RefPtr<dom::Element> tcElm = aTree->GetTreeBody();
   RefPtr<nsXULElement> tcXULElm = nsXULElement::FromNodeOrNull(tcElm);
   if (!tcXULElm) return nullptr;
 
@@ -449,8 +449,7 @@ XULTreeElement *nsCoreUtils::GetTree(nsIContent *aContent) {
 
 already_AddRefed<nsTreeColumn> nsCoreUtils::GetFirstSensibleColumn(
     XULTreeElement *aTree) {
-  RefPtr<nsTreeColumns> cols;
-  aTree->GetColumns(getter_AddRefs(cols));
+  RefPtr<nsTreeColumns> cols = aTree->GetColumns();
   if (!cols) return nullptr;
 
   RefPtr<nsTreeColumn> column = cols->GetFirstColumn();
@@ -462,8 +461,7 @@ already_AddRefed<nsTreeColumn> nsCoreUtils::GetFirstSensibleColumn(
 uint32_t nsCoreUtils::GetSensibleColumnCount(XULTreeElement *aTree) {
   uint32_t count = 0;
 
-  RefPtr<nsTreeColumns> cols;
-  aTree->GetColumns(getter_AddRefs(cols));
+  RefPtr<nsTreeColumns> cols = aTree->GetColumns();
   if (!cols) return count;
 
   nsTreeColumn *column = cols->GetFirstColumn();
diff --git a/accessible/xul/XULTreeAccessible.cpp b/accessible/xul/XULTreeAccessible.cpp
index 0409a84baf70..b7770a46c853 100644
--- a/accessible/xul/XULTreeAccessible.cpp
+++ b/accessible/xul/XULTreeAccessible.cpp
@@ -31,6 +31,7 @@
 #include "nsTreeBodyFrame.h"
 #include "nsTreeColumns.h"
 #include "nsTreeUtils.h"
+#include "mozilla/dom/XULTreeElementBinding.h"
 
 using namespace mozilla::a11y;
 
@@ -113,8 +114,7 @@ void XULTreeAccessible::Value(nsString& aValue) const {
   if (currentIndex >= 0) {
     RefPtr<nsTreeColumn> keyCol;
 
-    RefPtr<nsTreeColumns> cols;
-    mTree->GetColumns(getter_AddRefs(cols));
+    RefPtr<nsTreeColumns> cols = mTree->GetColumns();
     if (cols) keyCol = cols->GetKeyColumn();
 
     mTreeView->GetCellText(currentIndex, keyCol, aValue);
@@ -171,23 +171,21 @@ Accessible* XULTreeAccessible::ChildAtPoint(int32_t aX, int32_t aY,
   int32_t clientX = presContext->DevPixelsToIntCSSPixels(aX) - rootRect.X();
   int32_t clientY = presContext->DevPixelsToIntCSSPixels(aY) - rootRect.Y();
 
-  int32_t row = -1;
-  RefPtr<nsTreeColumn> column;
-  nsAutoString childEltUnused;
-  mTree->GetCellAt(clientX, clientY, &row, getter_AddRefs(column),
-                   childEltUnused);
+  ErrorResult rv;
+  dom::TreeCellInfo cellInfo;
+  mTree->GetCellAt(clientX, clientY, cellInfo, rv);
 
   // If we failed to find tree cell for the given point then it might be
   // tree columns.
-  if (row == -1 || !column)
+  if (cellInfo.mRow == -1 || !cellInfo.mCol)
     return AccessibleWrap::ChildAtPoint(aX, aY, aWhichChild);
 
-  Accessible* child = GetTreeItemAccessible(row);
+  Accessible* child = GetTreeItemAccessible(cellInfo.mRow);
   if (aWhichChild == eDeepestChild && child) {
     // Look for accessible cell for the found item accessible.
     RefPtr<XULTreeItemAccessibleBase> treeitem = do_QueryObject(child);
 
-    Accessible* cell = treeitem->GetCellAccessible(column);
+    Accessible* cell = treeitem->GetCellAccessible(cellInfo.mCol);
     if (cell) child = cell;
   }
 
@@ -524,8 +522,7 @@ void XULTreeAccessible::TreeViewInvalidated(int32_t aStartRow, int32_t aEndRow,
     endRow = rowCount - 1;
   }
 
-  RefPtr<nsTreeColumns> treeColumns;
-  mTree->GetColumns(getter_AddRefs(treeColumns));
+  RefPtr<nsTreeColumns> treeColumns = mTree->GetColumns();
   if (!treeColumns) return;
 
   int32_t endCol = aEndCol;
@@ -625,23 +622,19 @@ nsIntRect XULTreeItemAccessibleBase::BoundsInCSSPixels() const {
 
   RefPtr<nsTreeColumn> column = nsCoreUtils::GetFirstSensibleColumn(mTree);
 
-  int32_t x = 0, y = 0, width = 0, height = 0;
-  nsresult rv = mTree->GetCoordsForCellItem(mRow, column, EmptyString(), &x, &y,
-                                            &width, &height);
+  nsresult rv;
+  nsIntRect rect =
+      mTree->GetCoordsForCellItem(mRow, column, NS_LITERAL_STRING("cell"), rv);
   if (NS_FAILED(rv)) {
     return nsIntRect();
   }
 
-  boxObj->GetWidth(&width);
+  boxObj->GetWidth(&rect.width);
 
   int32_t tcX = 0, tcY = 0;
   boxObj->GetScreenX(&tcX);
   boxObj->GetScreenY(&tcY);
-
-  x = tcX;
-  y += tcY;
-
-  return nsIntRect(x, y, width, height);
+  return nsIntRect(tcX, rect.y + tcY, rect.width, rect.height);
 }
 
 nsRect XULTreeItemAccessibleBase::BoundsInAppUnits() const {
@@ -806,9 +799,8 @@ uint64_t XULTreeItemAccessibleBase::NativeState() const {
   if (FocusMgr()->IsFocused(this)) state |= states::FOCUSED;
 
   // invisible state
-  int32_t firstVisibleRow, lastVisibleRow;
-  mTree->GetFirstVisibleRow(&firstVisibleRow);
-  mTree->GetLastVisibleRow(&lastVisibleRow);
+  int32_t firstVisibleRow = mTree->GetFirstVisibleRow();
+  int32_t lastVisibleRow = mTree->GetLastVisibleRow();
   if (mRow < firstVisibleRow || mRow > lastVisibleRow)
     state |= states::INVISIBLE;
 
@@ -837,8 +829,7 @@ void XULTreeItemAccessibleBase::DispatchClickEvent(
     nsIContent* aContent, uint32_t aActionIndex) const {
   if (IsDefunct()) return;
 
-  RefPtr<nsTreeColumns> columns;
-  mTree->GetColumns(getter_AddRefs(columns));
+  RefPtr<nsTreeColumns> columns = mTree->GetColumns();
   if (!columns) return;
 
   // Get column and pseudo element.
@@ -874,8 +865,7 @@ bool XULTreeItemAccessibleBase::IsExpandable() const {
     bool isEmpty = false;
     mTreeView->IsContainerEmpty(mRow, &isEmpty);
     if (!isEmpty) {
-      RefPtr<nsTreeColumns> columns;
-      mTree->GetColumns(getter_AddRefs(columns));
+      RefPtr<nsTreeColumns> columns = mTree->GetColumns();
       if (columns) {
         nsTreeColumn* primaryColumn = columns->GetPrimaryColumn();
         if (primaryColumn && !nsCoreUtils::IsColumnHidden(primaryColumn))
@@ -946,8 +936,7 @@ void XULTreeItemAccessible::Shutdown() {
 }
 
 role XULTreeItemAccessible::NativeRole() const {
-  RefPtr<nsTreeColumns> columns;
-  mTree->GetColumns(getter_AddRefs(columns));
+  RefPtr<nsTreeColumns> columns = mTree->GetColumns();
   if (!columns) {
     NS_ERROR("No tree columns object in the tree!");
     return roles::NOTHING;
@@ -989,8 +978,7 @@ Accessible* XULTreeColumAccessible::GetSiblingAtOffset(int32_t aOffset,
 
   RefPtr<dom::XULTreeElement> tree = nsCoreUtils::GetTree(mContent);
   if (tree) {
-    nsCOMPtr<nsITreeView> treeView;
-    tree->GetView(getter_AddRefs(treeView));
+    nsCOMPtr<nsITreeView> treeView = tree->GetView();
     if (treeView) {
       int32_t rowCount = 0;
       treeView->GetRowCount(&rowCount);
diff --git a/accessible/xul/XULTreeGridAccessible.cpp b/accessible/xul/XULTreeGridAccessible.cpp
index e6e63e6e2152..0e0b8a45136c 100644
--- a/accessible/xul/XULTreeGridAccessible.cpp
+++ b/accessible/xul/XULTreeGridAccessible.cpp
@@ -23,6 +23,7 @@
 #include "nsComponentManagerUtils.h"
 #include "mozilla/dom/Element.h"
 #include "mozilla/dom/TreeColumnBinding.h"
+#include "mozilla/dom/XULTreeElementBinding.h"
 
 using namespace mozilla::a11y;
 using namespace mozilla;
@@ -169,8 +170,7 @@ void XULTreeGridAccessible::UnselectRow(uint32_t aRowIdx) {
 // XULTreeGridAccessible: Accessible implementation
 
 role XULTreeGridAccessible::NativeRole() const {
-  RefPtr<nsTreeColumns> treeColumns;
-  mTree->GetColumns(getter_AddRefs(treeColumns));
+  RefPtr<nsTreeColumns> treeColumns = mTree->GetColumns();
   if (!treeColumns) {
     NS_ERROR("No treecolumns object for tree!");
     return roles::NOTHING;
@@ -268,16 +268,14 @@ Accessible* XULTreeGridRowAccessible::ChildAtPoint(
   int32_t clientX = presContext->DevPixelsToIntCSSPixels(aX) - rootRect.X();
   int32_t clientY = presContext->DevPixelsToIntCSSPixels(aY) - rootRect.Y();
 
-  int32_t row = -1;
-  RefPtr<nsTreeColumn> column;
-  nsAutoString childEltUnused;
-  mTree->GetCellAt(clientX, clientY, &row, getter_AddRefs(column),
-                   childEltUnused);
+  ErrorResult rv;
+  dom::TreeCellInfo cellInfo;
+  mTree->GetCellAt(clientX, clientY, cellInfo, rv);
 
   // Return if we failed to find tree cell in the row for the given point.
-  if (row != mRow || !column) return nullptr;
+  if (cellInfo.mRow != mRow || !cellInfo.mCol) return nullptr;
 
-  return GetCellAccessible(column);
+  return GetCellAccessible(cellInfo.mCol);
 }
 
 Accessible* XULTreeGridRowAccessible::GetChildAt(uint32_t aIndex) const {
@@ -314,8 +312,7 @@ XULTreeGridCellAccessible* XULTreeGridRowAccessible::GetCellAccessible(
 
 void XULTreeGridRowAccessible::RowInvalidated(int32_t aStartColIdx,
                                               int32_t aEndColIdx) {
-  RefPtr<nsTreeColumns> treeColumns;
-  mTree->GetColumns(getter_AddRefs(treeColumns));
+  RefPtr<nsTreeColumns> treeColumns = mTree->GetColumns();
   if (!treeColumns) return;
 
   bool nameChanged = false;
@@ -410,9 +407,9 @@ nsIntRect XULTreeGridCellAccessible::BoundsInCSSPixels() const {
     return nsIntRect();
   }
 
-  int32_t x = 0, y = 0, width = 0, height = 0;
-  nsresult rv = mTree->GetCoordsForCellItem(
-      mRow, mColumn, NS_LITERAL_STRING("cell"), &x, &y, &width, &height);
+  nsresult rv;
+  nsIntRect rect =
+      mTree->GetCoordsForCellItem(mRow, mColumn, NS_LITERAL_STRING("cell"), rv);
   if (NS_FAILED(rv)) {
     return nsIntRect();
   }
@@ -420,10 +417,7 @@ nsIntRect XULTreeGridCellAccessible::BoundsInCSSPixels() const {
   int32_t tcX = 0, tcY = 0;
   boxObj->GetScreenX(&tcX);
   boxObj->GetScreenY(&tcY);
-  x += tcX;
-  y += tcY;
-
-  return nsIntRect(x, y, width, height);
+  return nsIntRect(rect.x + tcX, rect.y + tcY, rect.width, rect.height);
 }
 
 nsRect XULTreeGridCellAccessible::BoundsInAppUnits() const {
diff --git a/dom/xul/XULTreeElement.cpp b/dom/xul/XULTreeElement.cpp
index 4b13020d2dc1..659887d3f47d 100644
--- a/dom/xul/XULTreeElement.cpp
+++ b/dom/xul/XULTreeElement.cpp
@@ -110,41 +110,30 @@ nsTreeBodyFrame* XULTreeElement::GetTreeBodyFrame(bool aFlushLayout) {
   return mTreeBody;
 }
 
-nsresult XULTreeElement::GetView(nsITreeView** aView) {
+already_AddRefed<nsITreeView> XULTreeElement::GetView() {
   if (!mTreeBody) {
     if (!GetTreeBodyFrame()) {
-      // Don't return an uninitialised view
-      *aView = nullptr;
-      return NS_OK;
+      return nullptr;
     }
 
     if (mView) {
+      nsCOMPtr<nsITreeView> view;
       // Our new frame needs to initialise itself
-      return mTreeBody->GetView(aView);
+      mTreeBody->GetView(getter_AddRefs(view));
+      return view.forget();
     }
   }
   if (!mView) {
     // No tree builder, create a tree content view.
-    nsresult rv = NS_NewTreeContentView(getter_AddRefs(mView));
-    NS_ENSURE_SUCCESS(rv, rv);
+    if (NS_FAILED(NS_NewTreeContentView(getter_AddRefs(mView)))) {
+      return nullptr;
+    }
 
     // Initialise the frame and view
     mTreeBody->SetView(mView);
   }
-  NS_IF_ADDREF(*aView = mView);
-  return NS_OK;
-}
 
-already_AddRefed<nsITreeView> XULTreeElement::GetView(CallerType /* unused */) {
-  nsCOMPtr<nsITreeView> view;
-  GetView(getter_AddRefs(view));
-  return view.forget();
-}
-
-nsresult XULTreeElement::SetView(nsITreeView* aView) {
-  ErrorResult rv;
-  SetView(aView, CallerType::System, rv);
-  return rv.StealNSResult();
+  return do_AddRef(mView);
 }
 
 void XULTreeElement::SetView(nsITreeView* aView, CallerType aCallerType,
@@ -157,108 +146,98 @@ void XULTreeElement::SetView(nsITreeView* aView, CallerType aCallerType,
 
   mView = aView;
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->SetView(aView);
+  if (body) {
+    body->SetView(aView);
+  }
 }
 
 bool XULTreeElement::Focused() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->GetFocused();
+  if (body) {
+    return body->GetFocused();
+  }
   return false;
 }
 
-nsresult XULTreeElement::GetFocused(bool* aFocused) {
-  *aFocused = Focused();
-  return NS_OK;
-}
-
 void XULTreeElement::SetFocused(bool aFocused) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->SetFocused(aFocused);
-}
-
-nsresult XULTreeElement::GetTreeBody(Element** aElement) {
-  *aElement = nullptr;
-  nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->GetTreeBody(aElement);
-  return NS_OK;
+  if (body) {
+    body->SetFocused(aFocused);
+  }
 }
 
 already_AddRefed<Element> XULTreeElement::GetTreeBody() {
-  RefPtr<Element> el;
-  GetTreeBody(getter_AddRefs(el));
-  return el.forget();
+  nsTreeBodyFrame* body = GetTreeBodyFrame();
+  if (body) {
+    nsCOMPtr<Element> element;
+    body->GetTreeBody(getter_AddRefs(element));
+    return element.forget();
+  }
+
+  return nullptr;
 }
 
 already_AddRefed<nsTreeColumns> XULTreeElement::GetColumns() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->Columns();
+  if (body) {
+    return body->Columns();
+  }
   return nullptr;
 }
 
-nsresult XULTreeElement::GetColumns(nsTreeColumns** aColumns) {
-  *aColumns = GetColumns().take();
-  return NS_OK;
-}
-
 int32_t XULTreeElement::RowHeight() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->RowHeight();
+  if (body) {
+    return body->RowHeight();
+  }
   return 0;
 }
 
 int32_t XULTreeElement::RowWidth() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->RowWidth();
+  if (body) {
+    return body->RowWidth();
+  }
   return 0;
 }
 
-nsresult XULTreeElement::GetRowHeight(int32_t* aRowHeight) {
-  *aRowHeight = RowHeight();
-  return NS_OK;
-}
-
-nsresult XULTreeElement::GetRowWidth(int32_t* aRowWidth) {
-  *aRowWidth = RowWidth();
-  return NS_OK;
-}
-
 int32_t XULTreeElement::GetFirstVisibleRow() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->FirstVisibleRow();
+  if (body) {
+    return body->FirstVisibleRow();
+  }
   return 0;
 }
 
-nsresult XULTreeElement::GetFirstVisibleRow(int32_t* aFirstVisibleRow) {
-  *aFirstVisibleRow = GetFirstVisibleRow();
-  return NS_OK;
-}
-
 int32_t XULTreeElement::GetLastVisibleRow() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->LastVisibleRow();
+  if (body) {
+    return body->LastVisibleRow();
+  }
   return 0;
 }
 
-nsresult XULTreeElement::GetLastVisibleRow(int32_t* aLastVisibleRow) {
-  *aLastVisibleRow = GetLastVisibleRow();
-  return NS_OK;
-}
-
 int32_t XULTreeElement::HorizontalPosition() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->GetHorizontalPosition();
+  if (body) {
+    return body->GetHorizontalPosition();
+  }
   return 0;
 }
 
 int32_t XULTreeElement::GetPageLength() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->PageLength();
+  if (body) {
+    return body->PageLength();
+  }
   return 0;
 }
 
 void XULTreeElement::EnsureRowIsVisible(int32_t aRow) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->EnsureRowIsVisible(aRow);
+  if (body) {
+    body->EnsureRowIsVisible(aRow);
+  }
 }
 
 void XULTreeElement::EnsureCellIsVisible(int32_t aRow, nsTreeColumn* aCol,
@@ -291,32 +270,44 @@ void XULTreeElement::ScrollByLines(int32_t aNumLines) {
 
 void XULTreeElement::ScrollByPages(int32_t aNumPages) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->ScrollByPages(aNumPages);
+  if (body) {
+    body->ScrollByPages(aNumPages);
+  }
 }
 
 void XULTreeElement::Invalidate() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->Invalidate();
+  if (body) {
+    body->Invalidate();
+  }
 }
 
 void XULTreeElement::InvalidateColumn(nsTreeColumn* aCol) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->InvalidateColumn(aCol);
+  if (body) {
+    body->InvalidateColumn(aCol);
+  }
 }
 
 void XULTreeElement::InvalidateRow(int32_t aIndex) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->InvalidateRow(aIndex);
+  if (body) {
+    body->InvalidateRow(aIndex);
+  }
 }
 
 void XULTreeElement::InvalidateCell(int32_t aRow, nsTreeColumn* aCol) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->InvalidateCell(aRow, aCol);
+  if (body) {
+    body->InvalidateCell(aRow, aCol);
+  }
 }
 
 void XULTreeElement::InvalidateRange(int32_t aStart, int32_t aEnd) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->InvalidateRange(aStart, aEnd);
+  if (body) {
+    body->InvalidateRange(aStart, aEnd);
+  }
 }
 
 int32_t XULTreeElement::GetRowAt(int32_t x, int32_t y) {
@@ -327,82 +318,86 @@ int32_t XULTreeElement::GetRowAt(int32_t x, int32_t y) {
   return body->GetRowAt(x, y);
 }
 
-nsresult XULTreeElement::GetCellAt(int32_t aX, int32_t aY, int32_t* aRow,
-                                   nsTreeColumn** aCol, nsAString& aChildElt) {
-  *aRow = 0;
-  *aCol = nullptr;
+void XULTreeElement::GetCellAt(int32_t aX, int32_t aY, TreeCellInfo& aRetVal,
+                               ErrorResult& aRv) {
+  aRetVal.mRow = 0;
+  aRetVal.mCol = nullptr;
+
   nsTreeBodyFrame* body = GetTreeBodyFrame();
   if (body) {
     nsAutoCString element;
-    nsresult retval = body->GetCellAt(aX, aY, aRow, aCol, element);
-    CopyUTF8toUTF16(element, aChildElt);
-    return retval;
+    body->GetCellAt(aX, aY, &aRetVal.mRow, getter_AddRefs(aRetVal.mCol),
+                    element);
+    CopyUTF8toUTF16(element, aRetVal.mChildElt);
   }
-  return NS_OK;
 }
 
-void XULTreeElement::GetCellAt(int32_t x, int32_t y, TreeCellInfo& aRetVal,
-                               ErrorResult& aRv) {
-  GetCellAt(x, y, &aRetVal.mRow, getter_AddRefs(aRetVal.mCol),
-            aRetVal.mChildElt);
-}
+nsIntRect XULTreeElement::GetCoordsForCellItem(int32_t aRow, nsTreeColumn* aCol,
+                                               const nsAString& aElement,
+                                               nsresult& rv) {
+  rv = NS_OK;
+  nsIntRect rect;
 
-nsresult XULTreeElement::GetCoordsForCellItem(int32_t aRow, nsTreeColumn* aCol,
-                                              const nsAString& aElement,
-                                              int32_t* aX, int32_t* aY,
-                                              int32_t* aWidth,
-                                              int32_t* aHeight) {
-  *aX = *aY = *aWidth = *aHeight = 0;
   nsTreeBodyFrame* body = GetTreeBodyFrame();
   NS_ConvertUTF16toUTF8 element(aElement);
-  if (body)
-    return body->GetCoordsForCellItem(aRow, aCol, element, aX, aY, aWidth,
-                                      aHeight);
-  return NS_OK;
+  if (body) {
+    rv = body->GetCoordsForCellItem(aRow, aCol, element, &rect.x, &rect.y,
+                                    &rect.width, &rect.height);
+  }
+
+  return rect;
 }
 
 already_AddRefed<DOMRect> XULTreeElement::GetCoordsForCellItem(
-    int32_t row, nsTreeColumn& col, const nsAString& element,
+    int32_t aRow, nsTreeColumn& aCol, const nsAString& aElement,
     ErrorResult& aRv) {
-  int32_t x, y, w, h;
-  GetCoordsForCellItem(row, &col, element, &x, &y, &w, &h);
-  RefPtr<DOMRect> rect = new DOMRect(this, x, y, w, h);
-  return rect.forget();
+  nsresult rv;
+  nsIntRect rect = GetCoordsForCellItem(aRow, &aCol, aElement, rv);
+  aRv = rv;
+
+  RefPtr<DOMRect> domRect =
+      new DOMRect(this, rect.x, rect.y, rect.width, rect.height);
+  return domRect.forget();
 }
 
-nsresult XULTreeElement::IsCellCropped(int32_t aRow, nsTreeColumn* aCol,
-                                       bool* aIsCropped) {
-  *aIsCropped = false;
-  nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) return body->IsCellCropped(aRow, aCol, aIsCropped);
-  return NS_OK;
-}
-
-bool XULTreeElement::IsCellCropped(int32_t row, nsTreeColumn* col,
+bool XULTreeElement::IsCellCropped(int32_t aRow, nsTreeColumn* aCol,
                                    ErrorResult& aRv) {
-  bool ret;
-  aRv = IsCellCropped(row, col, &ret);
-  return ret;
+  bool cropped = false;
+
+  nsTreeBodyFrame* body = GetTreeBodyFrame();
+  if (body) {
+    aRv = body->IsCellCropped(aRow, aCol, &cropped);
+  }
+
+  return cropped;
 }
 
 void XULTreeElement::RowCountChanged(int32_t aIndex, int32_t aDelta) {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->RowCountChanged(aIndex, aDelta);
+  if (body) {
+    body->RowCountChanged(aIndex, aDelta);
+  }
 }
 
 void XULTreeElement::BeginUpdateBatch() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->BeginUpdateBatch();
+  if (body) {
+    body->BeginUpdateBatch();
+  }
 }
 
 void XULTreeElement::EndUpdateBatch() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->EndUpdateBatch();
+  if (body) {
+    body->EndUpdateBatch();
+  }
 }
 
 void XULTreeElement::ClearStyleAndImageCaches() {
   nsTreeBodyFrame* body = GetTreeBodyFrame();
-  if (body) body->ClearStyleAndImageCaches();
+  if (body) {
+    body->ClearStyleAndImageCaches();
+  }
 }
 
 void XULTreeElement::RemoveImageCacheEntry(int32_t aRowIndex,
diff --git a/dom/xul/XULTreeElement.h b/dom/xul/XULTreeElement.h
index 991fbc8ade2d..a556d01716c4 100644
--- a/dom/xul/XULTreeElement.h
+++ b/dom/xul/XULTreeElement.h
@@ -38,12 +38,15 @@ class XULTreeElement final : public nsXULElement {
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(XULTreeElement, nsXULElement)
 
-  nsTreeBodyFrame *GetTreeBodyFrame(bool aFlushLayout = false);
-  nsTreeBodyFrame *GetCachedTreeBodyFrame() { return mTreeBody; }
+  nsTreeBodyFrame* GetTreeBodyFrame(bool aFlushLayout = false);
+  nsTreeBodyFrame* GetCachedTreeBodyFrame() { return mTreeBody; }
 
   already_AddRefed<nsTreeColumns> GetColumns();
 
-  already_AddRefed<nsITreeView> GetView(CallerType /* unused */);
+  already_AddRefed<nsITreeView> GetView(CallerType /* unused */) {
+    return GetView();
+  }
+  already_AddRefed<nsITreeView> GetView();
 
   void SetView(nsITreeView* arg, CallerType aCallerType, ErrorResult& aRv);
 
@@ -57,7 +60,7 @@ class XULTreeElement final : public nsXULElement {
 
   int32_t HorizontalPosition();
 
-  void EnsureCellIsVisible(int32_t row, nsTreeColumn *col, ErrorResult &aRv);
+  void EnsureCellIsVisible(int32_t row, nsTreeColumn* col, ErrorResult& aRv);
 
   void ScrollToRow(int32_t aRow);
 
@@ -73,42 +76,29 @@ class XULTreeElement final : public nsXULElement {
 
   int32_t GetRowAt(int32_t x, int32_t y);
 
-  void GetCellAt(int32_t x, int32_t y, TreeCellInfo &aRetVal, ErrorResult &aRv);
+  void GetCellAt(int32_t x, int32_t y, TreeCellInfo& aRetVal, ErrorResult& aRv);
 
-  already_AddRefed<DOMRect> GetCoordsForCellItem(int32_t row, nsTreeColumn &col,
-                                                 const nsAString &element,
-                                                 ErrorResult &aRv);
+  nsIntRect GetCoordsForCellItem(int32_t aRow, nsTreeColumn* aCol,
+                                 const nsAString& aElement, nsresult& rv);
+  already_AddRefed<DOMRect> GetCoordsForCellItem(int32_t row, nsTreeColumn& col,
+                                                 const nsAString& element,
+                                                 ErrorResult& aRv);
 
-  bool IsCellCropped(int32_t row, nsTreeColumn *col, ErrorResult &aRv);
+  bool IsCellCropped(int32_t row, nsTreeColumn* col, ErrorResult& aRv);
 
-  void RemoveImageCacheEntry(int32_t row, nsTreeColumn &col, ErrorResult &aRv);
+  void RemoveImageCacheEntry(int32_t row, nsTreeColumn& col, ErrorResult& aRv);
 
   void SetFocused(bool aFocused);
   void EnsureRowIsVisible(int32_t index);
   void Invalidate(void);
-  void InvalidateColumn(nsTreeColumn *col);
+  void InvalidateColumn(nsTreeColumn* col);
   void InvalidateRow(int32_t index);
-  void InvalidateCell(int32_t row, nsTreeColumn *col);
+  void InvalidateCell(int32_t row, nsTreeColumn* col);
   void InvalidateRange(int32_t startIndex, int32_t endIndex);
   void RowCountChanged(int32_t index, int32_t count);
   void BeginUpdateBatch(void);
   void EndUpdateBatch(void);
   void ClearStyleAndImageCaches(void);
-  nsresult GetColumns(nsTreeColumns **aColumns);
-  nsresult GetView(nsITreeView **aView);
-  nsresult SetView(nsITreeView *aView);
-  nsresult GetFocused(bool *aFocused);
-  nsresult GetTreeBody(mozilla::dom::Element **aTreeBody);
-  nsresult GetRowHeight(int32_t *aRowHeight);
-  nsresult GetRowWidth(int32_t *aRowWidth);
-  nsresult GetFirstVisibleRow(int32_t *_retval);
-  nsresult GetLastVisibleRow(int32_t *_retval);
-  nsresult GetCellAt(int32_t x, int32_t y, int32_t *row, nsTreeColumn **col,
-                     nsAString &childElt);
-  nsresult GetCoordsForCellItem(int32_t row, nsTreeColumn *col,
-                                const nsAString &element, int32_t *x,
-                                int32_t *y, int32_t *width, int32_t *height);
-  nsresult IsCellCropped(int32_t row, nsTreeColumn *col, bool *_retval);
 
   virtual void UnbindFromTree(bool aDeep, bool aNullParent) override;
   virtual void DestroyContent() override;
@@ -123,7 +113,7 @@ class XULTreeElement final : public nsXULElement {
  protected:
   int32_t mCachedFirstVisibleRow;
 
-  nsTreeBodyFrame *mTreeBody;
+  nsTreeBodyFrame* mTreeBody;
   nsCOMPtr<nsITreeView> mView;
 
   virtual ~XULTreeElement() {}
diff --git a/layout/base/PresShell.cpp b/layout/base/PresShell.cpp
index 0a0b7b64fd4d..888d3826d352 100644
--- a/layout/base/PresShell.cpp
+++ b/layout/base/PresShell.cpp
@@ -7984,16 +7984,14 @@ void PresShell::GetCurrentItemAndPositionForElement(
       // which could provide the current focus coordinates?
       if (tree) {
         tree->EnsureRowIsVisible(currentIndex);
-        int32_t firstVisibleRow, rowHeight;
-        tree->GetFirstVisibleRow(&firstVisibleRow);
-        tree->GetRowHeight(&rowHeight);
+        int32_t firstVisibleRow = tree->GetFirstVisibleRow();
+        int32_t rowHeight = tree->RowHeight();
 
         extraTreeY += nsPresContext::CSSPixelsToAppUnits(
             (currentIndex - firstVisibleRow + 1) * rowHeight);
         istree = true;
 
-        RefPtr<nsTreeColumns> cols;
-        tree->GetColumns(getter_AddRefs(cols));
+        RefPtr<nsTreeColumns> cols = tree->GetColumns();
         if (cols) {
           nsTreeColumn* col = cols->GetFirstColumn();
           if (col) {
diff --git a/layout/xul/nsXULTooltipListener.cpp b/layout/xul/nsXULTooltipListener.cpp
index c31e085c2dfa..620d09cfdaf2 100644
--- a/layout/xul/nsXULTooltipListener.cpp
+++ b/layout/xul/nsXULTooltipListener.cpp
@@ -33,6 +33,7 @@
 #include "mozilla/dom/BoxObject.h"
 #include "mozilla/dom/MouseEvent.h"
 #include "mozilla/dom/TreeColumnBinding.h"
+#include "mozilla/dom/XULTreeElementBinding.h"
 #include "mozilla/TextEvents.h"
 
 using namespace mozilla;
@@ -337,10 +338,6 @@ void nsXULTooltipListener::CheckTreeBodyMove(MouseEvent* aMouseEvent) {
     int32_t x = aMouseEvent->ScreenX(CallerType::System);
     int32_t y = aMouseEvent->ScreenY(CallerType::System);
 
-    int32_t row;
-    RefPtr<nsTreeColumn> col;
-    nsAutoString obj;
-
     // subtract off the documentElement's boxObject
     int32_t boxX, boxY;
     bx->GetScreenX(&boxX);
@@ -348,7 +345,12 @@ void nsXULTooltipListener::CheckTreeBodyMove(MouseEvent* aMouseEvent) {
     x -= boxX;
     y -= boxY;
 
-    tree->GetCellAt(x, y, &row, getter_AddRefs(col), obj);
+    ErrorResult rv;
+    TreeCellInfo cellInfo;
+    tree->GetCellAt(x, y, cellInfo, rv);
+
+    int32_t row = cellInfo.mRow;
+    RefPtr<nsTreeColumn> col = cellInfo.mCol;
 
     // determine if we are going to need a titletip
     // XXX check the disabletitletips attribute on the tree content
@@ -357,9 +359,9 @@ void nsXULTooltipListener::CheckTreeBodyMove(MouseEvent* aMouseEvent) {
     if (col) {
       colType = col->Type();
     }
-    if (row >= 0 && obj.EqualsLiteral("text") &&
+    if (row >= 0 && cellInfo.mChildElt.EqualsLiteral("text") &&
         colType != TreeColumn_Binding::TYPE_PASSWORD) {
-      tree->IsCellCropped(row, col, &mNeedTitletip);
+      mNeedTitletip = tree->IsCellCropped(row, col, rv);
     }
 
     nsCOMPtr<nsIContent> currentTooltip = do_QueryReferent(mCurrentTooltip);
@@ -435,8 +437,7 @@ nsresult nsXULTooltipListener::ShowTooltip() {
 #ifdef MOZ_XUL
 static void SetTitletipLabel(XULTreeElement* aTree, Element* aTooltip,
                              int32_t aRow, nsTreeColumn* aCol) {
-  nsCOMPtr<nsITreeView> view;
-  aTree->GetView(getter_AddRefs(view));
+  nsCOMPtr<nsITreeView> view = aTree->GetView();
   if (view) {
     nsAutoString label;
 #ifdef DEBUG
diff --git a/layout/xul/tree/nsTreeBodyFrame.cpp b/layout/xul/tree/nsTreeBodyFrame.cpp
index 871696822283..e8ab01272f17 100644
--- a/layout/xul/tree/nsTreeBodyFrame.cpp
+++ b/layout/xul/tree/nsTreeBodyFrame.cpp
@@ -277,8 +277,7 @@ void nsTreeBodyFrame::EnsureView() {
 
     RefPtr<XULTreeElement> tree = GetBaseElement();
     if (tree) {
-      nsCOMPtr<nsITreeView> treeView;
-      tree->GetView(getter_AddRefs(treeView));
+      nsCOMPtr<nsITreeView> treeView = tree->GetView();
       if (treeView && weakFrame.IsAlive()) {
         int32_t rowIndex = tree->GetCachedTopVisibleRow();
 
diff --git a/layout/xul/tree/nsTreeColFrame.cpp b/layout/xul/tree/nsTreeColFrame.cpp
index 9a56a96c6055..7c5d5c187180 100644
--- a/layout/xul/tree/nsTreeColFrame.cpp
+++ b/layout/xul/tree/nsTreeColFrame.cpp
@@ -155,7 +155,7 @@ void nsTreeColFrame::InvalidateColumns(bool aCanWalkFrameTree) {
     RefPtr<nsTreeColumns> columns;
 
     if (aCanWalkFrameTree) {
-      tree->GetColumns(getter_AddRefs(columns));
+      columns = tree->GetColumns();
     } else {
       nsTreeBodyFrame* body = tree->GetCachedTreeBodyFrame();
       if (body) {
diff --git a/layout/xul/tree/nsTreeContentView.cpp b/layout/xul/tree/nsTreeContentView.cpp
index 1f029f25a13a..245b329ef9d9 100644
--- a/layout/xul/tree/nsTreeContentView.cpp
+++ b/layout/xul/tree/nsTreeContentView.cpp
@@ -518,8 +518,7 @@ nsTreeContentView::SetTree(XULTreeElement* aTree) {
       mDocument = document;
     }
 
-    RefPtr<dom::Element> bodyElement;
-    mTree->GetTreeBody(getter_AddRefs(bodyElement));
+    RefPtr<dom::Element> bodyElement = mTree->GetTreeBody();
     if (bodyElement) {
       mBody = bodyElement.forget();
       int32_t index = 0;
@@ -779,8 +778,7 @@ void nsTreeContentView::AttributeChanged(dom::Element* aElement,
   if (aElement->IsXULElement(nsGkAtoms::treecol)) {
     if (aAttribute == nsGkAtoms::properties) {
       if (mTree) {
-        RefPtr<nsTreeColumns> cols;
-        mTree->GetColumns(getter_AddRefs(cols));
+        RefPtr<nsTreeColumns> cols = mTree->GetColumns();
         if (cols) {
           RefPtr<nsTreeColumn> col = cols->GetColumnFor(aElement);
           mTree->InvalidateColumn(col);
diff --git a/layout/xul/tree/nsTreeSelection.cpp b/layout/xul/tree/nsTreeSelection.cpp
index 167222d9425c..25382d46db42 100644
--- a/layout/xul/tree/nsTreeSelection.cpp
+++ b/layout/xul/tree/nsTreeSelection.cpp
@@ -466,8 +466,7 @@ NS_IMETHODIMP nsTreeSelection::InvertSelection() {
 NS_IMETHODIMP nsTreeSelection::SelectAll() {
   if (!mTree) return NS_OK;
 
-  nsCOMPtr<nsITreeView> view;
-  mTree->GetView(getter_AddRefs(view));
+  nsCOMPtr<nsITreeView> view = mTree->GetView();
   if (!view) return NS_OK;
 
   int32_t rowCount;