diff -r 000000000000 -r 6474c204b198 editor/libeditor/base/ChangeAttributeTxn.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/editor/libeditor/base/ChangeAttributeTxn.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,72 @@
+/* -*- 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 ChangeAttributeTxn_h__
+#define ChangeAttributeTxn_h__
+
+#include "EditTxn.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsIDOMElement.h"
+#include "nsISupportsImpl.h"
+#include "nsString.h"
+#include "nscore.h"
+
+class nsIEditor;
+
+/**
+ * A transaction that changes an attribute of a content node. 
+ * This transaction covers add, remove, and change attribute.
+ */
+class ChangeAttributeTxn : public EditTxn
+{
+public:
+  /** Initialize the transaction.
+    * @param aEditor the object providing core editing operations
+    * @param aNode   the node whose attribute will be changed
+    * @param aAttribute the name of the attribute to change
+    * @param aValue     the new value for aAttribute, if aRemoveAttribute is false
+    * @param aRemoveAttribute if true, remove aAttribute from aNode
+    */
+  NS_IMETHOD Init(nsIEditor      *aEditor,
+                  nsIDOMElement  *aNode,
+                  const nsAString& aAttribute,
+                  const nsAString& aValue,
+                  bool aRemoveAttribute);
+
+  ChangeAttributeTxn();
+
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ChangeAttributeTxn, EditTxn)
+
+  NS_DECL_EDITTXN
+
+  NS_IMETHOD RedoTransaction();
+
+protected:
+
+  /** the editor that created this transaction */
+  nsIEditor*  mEditor;
+  
+  /** the element to operate upon */
+  nsCOMPtr<nsIDOMElement> mElement;
+  
+  /** the attribute to change */
+  nsString mAttribute;
+
+  /** the value to set the attribute to (ignored if mRemoveAttribute==true) */
+  nsString mValue;
+
+  /** the value to set the attribute to for undo */
+  nsString mUndoValue;
+
+  /** true if the mAttribute was set on mElement at the time of execution */
+  bool     mAttributeWasSet;
+
+  /** true if the operation is to remove mAttribute from mElement */
+  bool     mRemoveAttribute;
+};
+
+#endif