[Oilpan] Migrate most classes under core/animations to Oilpan heap.

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 330bcc6d35486b0edddbd6927604f8a42c3feed3..bd640a54dc216742b32e1ee516ed946a091386e9 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -360,7 +360,7 @@ ElementAnimations& Element::ensureElementAnimations()
 {
     ElementRareData& rareData = ensureElementRareData();
     if (!rareData.elementAnimations())
-        rareData.setElementAnimations(adoptPtrWillBeNoop(new ElementAnimations()));
+        rareData.setElementAnimations(new ElementAnimations);
     return *rareData.elementAnimations();
 }