1 files changed, 45 insertions, 0 deletions
diff --git a/layout/xul/nsStackFrame.h b/layout/xul/nsStackFrame.h
new file mode 100644
index 0000000000..12ecb955ee
--- /dev/null
+++ b/layout/xul/nsStackFrame.h
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+
+  Eric D Vaughan
+  A frame that can have multiple children. Only one child may be displayed at
+one time. So the can be flipped though like a Stack of cards.
+
+**/
+
+#ifndef nsStackFrame_h___
+#define nsStackFrame_h___
+
+#include "mozilla/Attributes.h"
+#include "nsBoxFrame.h"
+
+namespace mozilla {
+class PresShell;
+}  // namespace mozilla
+
+class nsStackFrame final : public nsBoxFrame {
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(nsStackFrame)
+
+  friend nsIFrame* NS_NewStackFrame(mozilla::PresShell* aPresShell,
+                                    ComputedStyle* aStyle);
+
+#ifdef DEBUG_FRAME_DUMP
+  virtual nsresult GetFrameName(nsAString& aResult) const override {
+    return MakeFrameName(u"Stack"_ns, aResult);
+  }
+#endif
+
+  virtual void BuildDisplayListForChildren(
+      nsDisplayListBuilder* aBuilder, const nsDisplayListSet& aLists) override;
+
+ protected:
+  explicit nsStackFrame(ComputedStyle* aStyle, nsPresContext* aPresContext);
+};  // class nsStackFrame
+
+#endif