Make compositingState explicit

Source/core/page/animation/ImplicitAnimation.cpp

Index: Source/core/page/animation/ImplicitAnimation.cpp
diff --git a/Source/core/page/animation/ImplicitAnimation.cpp b/Source/core/page/animation/ImplicitAnimation.cpp
index 9120c908e30b2df84aca0c725f73ac28c7e95901..6bb9bfcf69fdffbb37695cd3a4649eb7b657818e 100644
--- a/Source/core/page/animation/ImplicitAnimation.cpp
+++ b/Source/core/page/animation/ImplicitAnimation.cpp
@@ -104,7 +104,7 @@ void ImplicitAnimation::getAnimatedStyle(RefPtr<RenderStyle>& animatedStyle)
 
 bool ImplicitAnimation::startAnimation(double timeOffset)
 {
-    if (m_object && m_object->isComposited())
+    if (m_object && m_object->compositingState() == PaintsIntoOwnBacking)
         return toRenderBoxModelObject(m_object)->startTransition(timeOffset, m_animatingProperty, m_fromStyle.get(), m_toStyle.get());
 
     return false;
@@ -115,7 +115,7 @@ void ImplicitAnimation::pauseAnimation(double timeOffset)
     if (!m_object)
         return;
 
-    if (m_object->isComposited())
+    if (m_object->compositingState() == PaintsIntoOwnBacking)
         toRenderBoxModelObject(m_object)->transitionPaused(timeOffset, m_animatingProperty);
 
     // Restore the original (unanimated) style
@@ -125,7 +125,7 @@ void ImplicitAnimation::pauseAnimation(double timeOffset)
 
 void ImplicitAnimation::endAnimation()
 {
-    if (m_object && m_object->isComposited())
+    if (m_object && m_object->compositingState() == PaintsIntoOwnBacking)
         toRenderBoxModelObject(m_object)->transitionFinished(m_animatingProperty);
 }