--- a/dom/smil/nsSMILCSSProperty.cpp
+++ b/dom/smil/nsSMILCSSProperty.cpp
@@ -23,17 +23,18 @@ using namespace mozilla::dom;
 // Class Methods
 nsSMILCSSProperty::nsSMILCSSProperty(nsCSSPropertyID aPropID,
                                      Element* aElement,
                                      nsStyleContext* aBaseStyleContext)
   : mPropID(aPropID)
   , mElement(aElement)
   , mBaseStyleContext(aBaseStyleContext)
 {
-  MOZ_ASSERT(IsPropertyAnimatable(mPropID),
+  MOZ_ASSERT(IsPropertyAnimatable(mPropID,
+               aElement->OwnerDoc()->GetStyleBackendType()),
              "Creating a nsSMILCSSProperty for a property "
              "that's not supported for animation");
 }
 
 nsSMILValue
 nsSMILCSSProperty::GetBaseValue() const
 {
   // To benefit from Return Value Optimization and avoid copy constructor calls
@@ -88,17 +89,19 @@ nsSMILCSSProperty::GetBaseValue() const
 }
 
 nsresult
 nsSMILCSSProperty::ValueFromString(const nsAString& aStr,
                                    const SVGAnimationElement* aSrcElement,
                                    nsSMILValue& aValue,
                                    bool& aPreventCachingOfSandwich) const
 {
-  NS_ENSURE_TRUE(IsPropertyAnimatable(mPropID), NS_ERROR_FAILURE);
+  NS_ENSURE_TRUE(IsPropertyAnimatable(mPropID,
+                   mElement->OwnerDoc()->GetStyleBackendType()),
+                 NS_ERROR_FAILURE);
 
   nsSMILCSSValueType::ValueFromString(mPropID, mElement, aStr, aValue,
       &aPreventCachingOfSandwich);
 
   if (aValue.IsNull()) {
     return NS_ERROR_FAILURE;
   }
 
@@ -109,17 +112,19 @@ nsSMILCSSProperty::ValueFromString(const
     aPreventCachingOfSandwich = true;
   }
   return NS_OK;
 }
 
 nsresult
 nsSMILCSSProperty::SetAnimValue(const nsSMILValue& aValue)
 {
-  NS_ENSURE_TRUE(IsPropertyAnimatable(mPropID), NS_ERROR_FAILURE);
+  NS_ENSURE_TRUE(IsPropertyAnimatable(mPropID,
+                   mElement->OwnerDoc()->GetStyleBackendType()),
+                 NS_ERROR_FAILURE);
 
   // Convert nsSMILValue to string
   nsAutoString valStr;
   nsSMILCSSValueType::ValueToString(aValue, valStr);
 
   // Use string value to style the target element
   nsICSSDeclaration* overrideDecl = mElement->GetSMILOverrideStyle();
   if (overrideDecl) {
@@ -141,18 +146,25 @@ nsSMILCSSProperty::ClearAnimValue()
   if (overrideDecl) {
     overrideDecl->SetPropertyValue(mPropID, EmptyString());
   }
 }
 
 // Based on http://www.w3.org/TR/SVG/propidx.html
 // static
 bool
-nsSMILCSSProperty::IsPropertyAnimatable(nsCSSPropertyID aPropID)
+nsSMILCSSProperty::IsPropertyAnimatable(nsCSSPropertyID aPropID,
+                                        StyleBackendType aBackend)
 {
+  // Bug 1353918: Drop this check
+  if (aBackend == StyleBackendType::Servo &&
+      !Servo_Property_IsAnimatable(aPropID)) {
+    return false;
+  }
+
   // NOTE: Right now, Gecko doesn't recognize the following properties from
   // the SVG Property Index:
   //   alignment-baseline
   //   baseline-shift
   //   color-profile
   //   color-rendering
   //   glyph-orientation-horizontal
   //   glyph-orientation-vertical

--- a/dom/smil/nsSMILCSSProperty.h
+++ b/dom/smil/nsSMILCSSProperty.h
@@ -5,16 +5,17 @@
  * 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 "mozilla/StyleBackendType.h"
 #include "nsISMILAttr.h"
 #include "nsIAtom.h"
 #include "nsCSSPropertyID.h"
 #include "nsCSSValue.h"
 
 class nsStyleContext;
 
 namespace mozilla {
@@ -53,20 +54,24 @@ public:
   virtual nsresult    SetAnimValue(const nsSMILValue& aValue) override;
   virtual void        ClearAnimValue() override;
 
   /**
    * Utility method - returns true if the given property is supported for
    * SMIL animation.
    *
    * @param   aProperty  The property to check for animation support.
+   * @param   aBackend   The style backend to check for animation support.
+   *                     This is a temporary measure until the Servo backend
+   *                     supports all animatable properties (bug 1353918).
    * @return  true if the given property is supported for SMIL animation, or
    *          false otherwise
    */
-  static bool IsPropertyAnimatable(nsCSSPropertyID aPropID);
+  static bool IsPropertyAnimatable(nsCSSPropertyID aPropID,
+                                   mozilla::StyleBackendType aBackend);
 
 protected:
   nsCSSPropertyID 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;

--- a/dom/smil/nsSMILCompositor.cpp
+++ b/dom/smil/nsSMILCompositor.cpp
@@ -155,17 +155,18 @@ nsSMILCompositor::GetCSSPropertyToAnimat
   if (mKey.mAttributeNamespaceID != kNameSpaceID_None) {
     return eCSSProperty_UNKNOWN;
   }
 
   nsCSSPropertyID propID =
     nsCSSProps::LookupProperty(nsDependentAtomString(mKey.mAttributeName),
                                CSSEnabledState::eForAllContent);
 
-  if (!nsSMILCSSProperty::IsPropertyAnimatable(propID)) {
+  if (!nsSMILCSSProperty::IsPropertyAnimatable(propID,
+        mKey.mElement->OwnerDoc()->GetStyleBackendType())) {
     return eCSSProperty_UNKNOWN;
   }
 
   // If we are animating the 'width' or 'height' of an outer SVG
   // element we should animate it as a CSS property, but for other elements
   // (e.g. <rect>) we should animate it as a length attribute.
   // The easiest way to test for an outer SVG element, is to see if it is an
   // SVG-namespace element mapping its width/height attribute to style.