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

Source/core/animation/ElementAnimations.cpp

Index: Source/core/animation/ElementAnimations.cpp
diff --git a/Source/core/animation/ElementAnimations.cpp b/Source/core/animation/ElementAnimations.cpp
index f12a4c8c8376c1fb15f6c0ced36e7384a43b4d56..34ae5192ad0d873bcefd7f9d887d81ca59e97724 100644
--- a/Source/core/animation/ElementAnimations.cpp
+++ b/Source/core/animation/ElementAnimations.cpp
@@ -42,11 +42,6 @@ ElementAnimations::ElementAnimations()
 
 ElementAnimations::~ElementAnimations()
 {
-#if !ENABLE(OILPAN)
-    for (Animation* animation : m_animations)
-        animation->notifyElementDestroyed();
-    m_animations.clear();
-#endif
 }
 
 void ElementAnimations::updateAnimationFlags(ComputedStyle& style)
@@ -83,19 +78,15 @@ void ElementAnimations::restartAnimationOnCompositor()
 
 DEFINE_TRACE(ElementAnimations)
 {
-#if ENABLE(OILPAN)
     visitor->trace(m_cssAnimations);
     visitor->trace(m_defaultStack);
+#if ENABLE(OILPAN)
     visitor->trace(m_players);
 #endif
 }
 
 const ComputedStyle* ElementAnimations::baseComputedStyle() const
 {
-#if !ENABLE(ASSERT)
-    if (isAnimationStyleChange())
-        return m_baseComputedStyle.get();
-#endif
     return nullptr;
 }