diff -r 000000000000 -r 6474c204b198 dom/smil/nsSMILMappedAttribute.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/smil/nsSMILMappedAttribute.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,55 @@
+/* -*- 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/. */
+
+/* representation of a SMIL-animatable mapped attribute on an element */
+
+#ifndef NS_SMILMAPPEDATTRIBUTE_H_
+#define NS_SMILMAPPEDATTRIBUTE_H_
+
+#include "mozilla/Attributes.h"
+#include "nsSMILCSSProperty.h"
+
+/* We'll use the empty-string atom |nsGkAtoms::_empty| as the key for storing
+ * an element's animated content style rule in its Property Table, under the
+ * property-category SMIL_MAPPED_ATTR_ANIMVAL.  Everything else stored in that
+ * category is keyed off of the XML attribute name, so the empty string is a
+ * good "reserved" key to use for storing the style rule (since XML attributes
+ * all have nonempty names).
+ */
+#define SMIL_MAPPED_ATTR_STYLERULE_ATOM nsGkAtoms::_empty
+
+/**
+ * nsSMILMappedAttribute: Implements the nsISMILAttr interface for SMIL
+ * animations whose targets are attributes that map to CSS properties.  An
+ * instance of this class represents a particular animation-targeted mapped
+ * attribute on a particular element.
+ */
+class nsSMILMappedAttribute : public nsSMILCSSProperty {
+public:
+  /**
+   * Constructs a new nsSMILMappedAttribute.
+   *
+   * @param  aPropID   The CSS property for the mapped attribute we're
+   *                   interested in animating.
+   * @param  aElement  The element whose attribute is being animated.
+   */
+  nsSMILMappedAttribute(nsCSSProperty aPropID, mozilla::dom::Element* aElement) :
+    nsSMILCSSProperty(aPropID, aElement) {}
+
+  // nsISMILAttr methods
+  virtual nsresult ValueFromString(const nsAString& aStr,
+                                   const mozilla::dom::SVGAnimationElement* aSrcElement,
+                                   nsSMILValue& aValue,
+                                   bool& aPreventCachingOfSandwich) const MOZ_OVERRIDE;
+  virtual nsSMILValue GetBaseValue() const MOZ_OVERRIDE;
+  virtual nsresult    SetAnimValue(const nsSMILValue& aValue) MOZ_OVERRIDE;
+  virtual void        ClearAnimValue() MOZ_OVERRIDE;
+
+protected:
+  // Helper Methods
+  void FlushChangesToTargetAttr() const;
+  already_AddRefed<nsIAtom> GetAttrNameAtom() const;
+};
+#endif // NS_SMILMAPPEDATTRIBUTE_H_