Bug 1361183 - Check Element::MayHaveAnimations() in EffectSet::GetEffectSet(). r=birtles

We can early return to call MayHaveAnimations() (and it should be fast) since
we set the flag in EffectSet::GetOrCreateEffectSet(),

MozReview-Commit-ID: 2UfWVVi6nY5

--HG--
extra : rebase_source : 97e98bf1fb9e725a107ed3200b95921375bfb637

dom/animation/EffectSet.cpp

@@ -42,6 +42,10 @@ EffectSet::Traverse(nsCycleCollectionTraversalCallback& aCallback)
 EffectSet::GetEffectSet(const dom::Element* aElement,
                         CSSPseudoElementType aPseudoType)
 {
+  if (!aElement->MayHaveAnimations()) {
+    return nullptr;
+  }
+
   nsIAtom* propName = GetEffectSetPropertyAtom(aPseudoType);
   return static_cast<EffectSet*>(aElement->GetProperty(propName));
 }
@@ -56,10 +60,6 @@ EffectSet::GetEffectSet(const nsIFrame* aFrame)
     return nullptr;
   }
 
-  if (!target->mElement->MayHaveAnimations()) {
-    return nullptr;
-  }
-
   return GetEffectSet(target->mElement, target->mPseudoType);
 }