diff -r 000000000000 -r 6474c204b198 dom/smil/nsSMILSetAnimationFunction.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/smil/nsSMILSetAnimationFunction.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,67 @@
+/* -*- 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 NS_SMILSETANIMATIONFUNCTION_H_
+#define NS_SMILSETANIMATIONFUNCTION_H_
+
+#include "mozilla/Attributes.h"
+#include "nsSMILAnimationFunction.h"
+
+//----------------------------------------------------------------------
+// nsSMILSetAnimationFunction
+//
+// Subclass of nsSMILAnimationFunction that limits the behaviour to that offered
+// by a <set> element.
+//
+class nsSMILSetAnimationFunction : public nsSMILAnimationFunction
+{
+public:
+  /*
+   * Sets animation-specific attributes (or marks them dirty, in the case
+   * of from/to/by/values).
+   *
+   * @param aAttribute The attribute being set
+   * @param aValue     The updated value of the attribute.
+   * @param aResult    The nsAttrValue object that may be used for storing the
+   *                   parsed result.
+   * @param aParseResult  Outparam used for reporting parse errors. Will be set
+   *                      to NS_OK if everything succeeds.
+   * @returns true if aAttribute is a recognized animation-related
+   *          attribute; false otherwise.
+   */
+  virtual bool SetAttr(nsIAtom* aAttribute, const nsAString& aValue,
+                         nsAttrValue& aResult, nsresult* aParseResult = nullptr) MOZ_OVERRIDE;
+
+  /*
+   * Unsets the given attribute.
+   *
+   * @returns true if aAttribute is a recognized animation-related
+   *          attribute; false otherwise.
+   */
+  virtual bool UnsetAttr(nsIAtom* aAttribute) MOZ_OVERRIDE;
+
+protected:
+  // Although <set> animation might look like to-animation, unlike to-animation,
+  // it never interpolates values.
+  // Returning false here will mean this animation function gets treated as
+  // a single-valued function and no interpolation will be attempted.
+  virtual bool IsToAnimation() const MOZ_OVERRIDE {
+    return false;
+  }
+
+  // <set> applies the exact same value across the simple duration.
+  virtual bool IsValueFixedForSimpleDuration() const MOZ_OVERRIDE {
+    return true;
+  }
+  virtual bool               HasAttr(nsIAtom* aAttName) const MOZ_OVERRIDE;
+  virtual const nsAttrValue* GetAttr(nsIAtom* aAttName) const MOZ_OVERRIDE;
+  virtual bool               GetAttr(nsIAtom* aAttName,
+                                     nsAString& aResult) const MOZ_OVERRIDE;
+  virtual bool WillReplace() const MOZ_OVERRIDE;
+
+  bool IsDisallowedAttribute(const nsIAtom* aAttribute) const;
+};
+
+#endif // NS_SMILSETANIMATIONFUNCTION_H_