diff -r 000000000000 -r 6474c204b198 dom/smil/nsSMILCSSProperty.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/smil/nsSMILCSSProperty.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,66 @@
+/* -*- 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 CSS property on an element */
+
+#ifndef NS_SMILCSSPROPERTY_H_
+#define NS_SMILCSSPROPERTY_H_
+
+#include "mozilla/Attributes.h"
+#include "nsISMILAttr.h"
+#include "nsIAtom.h"
+#include "nsCSSProperty.h"
+#include "nsCSSValue.h"
+
+namespace mozilla {
+namespace dom {
+class Element;
+} // namespace dom
+} // namespace mozilla
+
+/**
+ * nsSMILCSSProperty: Implements the nsISMILAttr interface for SMIL animations
+ * that target CSS properties.  Represents a particular animation-targeted CSS
+ * property on a particular element.
+ */
+class nsSMILCSSProperty : public nsISMILAttr
+{
+public:
+  /**
+   * Constructs a new nsSMILCSSProperty.
+   * @param  aPropID   The CSS property we're interested in animating.
+   * @param  aElement  The element whose CSS property is being animated.
+   */
+  nsSMILCSSProperty(nsCSSProperty aPropID, mozilla::dom::Element* 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;
+
+  /**
+   * Utility method - returns true if the given property is supported for
+   * SMIL animation.
+   *
+   * @param   aProperty  The property to check for animation support.
+   * @return  true if the given property is supported for SMIL animation, or
+   *          false otherwise
+   */
+  static bool IsPropertyAnimatable(nsCSSProperty aPropID);
+
+protected:
+  nsCSSProperty mPropID;
+  // Using non-refcounted pointer for mElement -- we know mElement will stay
+  // alive for my lifetime because a nsISMILAttr (like me) only lives as long
+  // as the Compositing step, and DOM elements don't get a chance to die during
+  // that time.
+  mozilla::dom::Element*   mElement;
+};
+
+#endif // NS_SMILCSSPROPERTY_H_