[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 c8033444844eb4eadf59ca737ca7a7b009a090f6..f41d18cd4d0f7d56e2455867c3e02180a93908f8 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -343,7 +343,7 @@ ElementAnimations& Element::ensureElementAnimations()
 {
     ElementRareData& rareData = ensureElementRareData();
     if (!rareData.elementAnimations())
-        rareData.setElementAnimations(adoptPtrWillBeNoop(new ElementAnimations()));
+        rareData.setElementAnimations(new ElementAnimations);
     return *rareData.elementAnimations();
 }