diff -r 000000000000 -r 6474c204b198 layout/xul/tree/nsTreeImageListener.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/layout/xul/tree/nsTreeImageListener.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#ifndef nsTreeImageListener_h__
+#define nsTreeImageListener_h__
+
+#include "nsString.h"
+#include "nsCOMPtr.h"
+#include "nsITreeColumns.h"
+#include "nsTreeBodyFrame.h"
+#include "mozilla/Attributes.h"
+
+// This class handles image load observation.
+class nsTreeImageListener MOZ_FINAL : public imgINotificationObserver
+{
+public:
+  nsTreeImageListener(nsTreeBodyFrame *aTreeFrame);
+  ~nsTreeImageListener();
+
+  NS_DECL_ISUPPORTS
+  NS_DECL_IMGINOTIFICATIONOBSERVER
+
+  NS_IMETHOD ClearFrame();
+
+  friend class nsTreeBodyFrame;
+
+protected:
+  void UnsuppressInvalidation() { mInvalidationSuppressed = false; }
+  void Invalidate();
+  void AddCell(int32_t aIndex, nsITreeColumn* aCol);
+
+private:
+  nsTreeBodyFrame* mTreeFrame;
+
+  // A guard that prevents us from recursive painting.
+  bool mInvalidationSuppressed;
+
+  class InvalidationArea {
+    public:
+      InvalidationArea(nsITreeColumn* aCol);
+      ~InvalidationArea() { delete mNext; }
+
+      friend class nsTreeImageListener;
+
+    protected:
+      void AddRow(int32_t aIndex);
+      nsITreeColumn* GetCol() { return mCol.get(); }
+      int32_t GetMin() { return mMin; }
+      int32_t GetMax() { return mMax; }
+      InvalidationArea* GetNext() { return mNext; }
+      void SetNext(InvalidationArea* aNext) { mNext = aNext; }
+
+    private:
+      nsCOMPtr<nsITreeColumn> mCol;
+      int32_t                 mMin;
+      int32_t                 mMax;
+      InvalidationArea*       mNext;
+  };
+
+  InvalidationArea* mInvalidationArea;
+};
+
+#endif // nsTreeImageListener_h__