diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 1e88be2e5c4..95659f02b81 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -1803,7 +1803,12 @@ Element::SetSMILOverrideStyleRule(css::StyleRule* aStyleRule,
     if (doc) {
       nsCOMPtr<nsIPresShell> shell = doc->GetShell();
       if (shell) {
-        shell->RestyleForAnimation(this, eRestyle_StyleAttribute);
+        // Pass both eRestyle_StyleAttribute and
+        // eRestyle_StyleAttribute_Animations since we don't know if
+        // this style represents only the ticking of an existing
+        // animation or whether it's a new or changed animation.
+        shell->RestyleForAnimation(this, eRestyle_StyleAttribute |
+                                         eRestyle_StyleAttribute_Animations);
       }
     }
   }
diff --git a/dom/smil/nsSMILAnimationController.cpp b/dom/smil/nsSMILAnimationController.cpp
index 3c6f9486282..8bb9572a4c5 100644
--- a/dom/smil/nsSMILAnimationController.cpp
+++ b/dom/smil/nsSMILAnimationController.cpp
@@ -832,7 +832,7 @@ nsSMILAnimationController::AddStyleUpdate(AnimationElementPtrKey* aKey,
   // Element::GetSMILOverrideStyleRule (via nsSMILCSSProperty objects),
   // and mIsCSS false means the rules are nsSMILMappedAttribute objects
   // returned from nsSVGElement::GetAnimatedContentStyleRule.
-  nsRestyleHint rshint = key.mIsCSS ? eRestyle_StyleAttribute
+  nsRestyleHint rshint = key.mIsCSS ? eRestyle_StyleAttribute_Animations
                                     : eRestyle_SVGAttrAnimations;
   restyleTracker->AddPendingRestyle(key.mElement, rshint, nsChangeHint(0));
 
diff --git a/layout/base/nsChangeHint.h b/layout/base/nsChangeHint.h
index a8b3d981e69..edc497ce13a 100644
--- a/layout/base/nsChangeHint.h
+++ b/layout/base/nsChangeHint.h
@@ -348,24 +348,30 @@ enum nsRestyleHint {
   // work.)  Supported only for element style contexts and not for
   // pseudo-elements or anonymous boxes, on which it converts to
   // eRestyle_Self.
+  // If the change is for the advance of a declarative animation, use
+  // the value below instead.
   eRestyle_StyleAttribute = (1<<6),
 
+  // Same as eRestyle_StyleAttribute, but for when the change results
+  // from the advance of a declarative animation.
+  eRestyle_StyleAttribute_Animations = (1<<7),
+
   // Continue the restyling process to the current frame's children even
   // if this frame's restyling resulted in no style changes.
-  eRestyle_Force = (1<<7),
+  eRestyle_Force = (1<<8),
 
   // Continue the restyling process to all of the current frame's
   // descendants, even if any frame's restyling resulted in no style
   // changes.  (Implies eRestyle_Force.)  Note that this is weaker than
   // eRestyle_Subtree, which makes us rerun selector matching on all
   // descendants rather than just continuing the restyling process.
-  eRestyle_ForceDescendants = (1<<8),
+  eRestyle_ForceDescendants = (1<<9),
 
   // Useful unions:
   eRestyle_AllHintsWithAnimations = eRestyle_CSSTransitions |
                                     eRestyle_CSSAnimations |
                                     eRestyle_SVGAttrAnimations |
-                                    eRestyle_StyleAttribute,
+                                    eRestyle_StyleAttribute_Animations,
 };
 
 // The functions below need an integral type to cast to to avoid
diff --git a/layout/style/nsStyleSet.cpp b/layout/style/nsStyleSet.cpp
index e3f3292b3d8..7c54892eb65 100644
--- a/layout/style/nsStyleSet.cpp
+++ b/layout/style/nsStyleSet.cpp
@@ -1378,12 +1378,14 @@ static const CascadeLevel gCascadeLevels[] = {
   { nsStyleSet::eSVGAttrAnimationSheet, false, false, eRestyle_SVGAttrAnimations },
   { nsStyleSet::eDocSheet,              false, false, nsRestyleHint(0) },
   { nsStyleSet::eScopedDocSheet,        false, false, nsRestyleHint(0) },
-  { nsStyleSet::eStyleAttrSheet,        false, true,  eRestyle_StyleAttribute },
+  { nsStyleSet::eStyleAttrSheet,        false, true,  eRestyle_StyleAttribute |
+                                                      eRestyle_StyleAttribute_Animations },
   { nsStyleSet::eOverrideSheet,         false, false, nsRestyleHint(0) },
   { nsStyleSet::eAnimationSheet,        false, false, eRestyle_CSSAnimations },
   { nsStyleSet::eScopedDocSheet,        true,  false, nsRestyleHint(0) },
   { nsStyleSet::eDocSheet,              true,  false, nsRestyleHint(0) },
-  { nsStyleSet::eStyleAttrSheet,        true,  false, eRestyle_StyleAttribute },
+  { nsStyleSet::eStyleAttrSheet,        true,  false, eRestyle_StyleAttribute |
+                                                      eRestyle_StyleAttribute_Animations },
   { nsStyleSet::eOverrideSheet,         true,  false, nsRestyleHint(0) },
   { nsStyleSet::eUserSheet,             true,  false, nsRestyleHint(0) },
   { nsStyleSet::eAgentSheet,            true,  false, nsRestyleHint(0) },
@@ -1409,6 +1411,7 @@ nsStyleSet::RuleNodeWithReplacement(Element* aElement,
                                  eRestyle_CSSAnimations |
                                  eRestyle_SVGAttrAnimations |
                                  eRestyle_StyleAttribute |
+                                 eRestyle_StyleAttribute_Animations |
                                  eRestyle_Force |
                                  eRestyle_ForceDescendants)),
              "unexpected replacement bits");
@@ -1449,8 +1452,8 @@ nsStyleSet::RuleNodeWithReplacement(Element* aElement,
                         level->mCheckForImportantRules && doReplace);
 
     if (doReplace) {
-      switch (level->mLevelReplacementHint) {
-        case eRestyle_CSSAnimations: {
+      switch (level->mLevel) {
+        case nsStyleSet::eAnimationSheet: {
           if (aPseudoType == nsCSSPseudoElements::ePseudo_NotPseudoElement ||
               aPseudoType == nsCSSPseudoElements::ePseudo_before ||
               aPseudoType == nsCSSPseudoElements::ePseudo_after) {
@@ -1462,7 +1465,7 @@ nsStyleSet::RuleNodeWithReplacement(Element* aElement,
           }
           break;
         }
-        case eRestyle_CSSTransitions: {
+        case nsStyleSet::eTransitionSheet: {
           if (aPseudoType == nsCSSPseudoElements::ePseudo_NotPseudoElement ||
               aPseudoType == nsCSSPseudoElements::ePseudo_before ||
               aPseudoType == nsCSSPseudoElements::ePseudo_after) {
@@ -1474,7 +1477,7 @@ nsStyleSet::RuleNodeWithReplacement(Element* aElement,
           }
           break;
         }
-        case eRestyle_SVGAttrAnimations: {
+        case nsStyleSet::eSVGAttrAnimationSheet: {
           SVGAttrAnimationRuleProcessor* ruleProcessor =
             static_cast<SVGAttrAnimationRuleProcessor*>(
               mRuleProcessors[eSVGAttrAnimationSheet].get());
@@ -1484,7 +1487,7 @@ nsStyleSet::RuleNodeWithReplacement(Element* aElement,
           }
           break;
         }
-        case eRestyle_StyleAttribute: {
+        case nsStyleSet::eStyleAttrSheet: {
           if (!level->mIsImportant) {
             // First time through, we handle the non-!important rule.
             nsHTMLCSSStyleSheet* ruleProcessor =