Revert "Make compositingState explicit (re-land #2 with bogus ASSERT removed)"

Source/core/css/CSSComputedStyleDeclaration.cpp

Index: Source/core/css/CSSComputedStyleDeclaration.cpp
diff --git a/Source/core/css/CSSComputedStyleDeclaration.cpp b/Source/core/css/CSSComputedStyleDeclaration.cpp
index 60612be6d0f1b315a5e41210c37ab01d2f429154..2339acf9177f0ff3d98630bffc5e8913789bae2b 100644
--- a/Source/core/css/CSSComputedStyleDeclaration.cpp
+++ b/Source/core/css/CSSComputedStyleDeclaration.cpp
@@ -1616,8 +1616,7 @@ PassRefPtr<RenderStyle> CSSComputedStyleDeclaration::computeRenderStyle(CSSPrope
     Node* styledNode = this->styledNode();
     ASSERT(styledNode);
     RenderObject* renderer = styledNode->renderer();
-    if (renderer && renderer->compositingState() == PaintsIntoOwnBacking
-        && !RuntimeEnabledFeatures::webAnimationsCSSEnabled() && AnimationController::supportsAcceleratedAnimationOfProperty(propertyID)) {
+    if (renderer && renderer->isComposited() && !RuntimeEnabledFeatures::webAnimationsCSSEnabled() && AnimationController::supportsAcceleratedAnimationOfProperty(propertyID)) {
         AnimationUpdateBlock animationUpdateBlock(renderer->animation());
         if (m_pseudoElementSpecifier && !styledNode->isPseudoElement()) {
             // FIXME: This cached pseudo style will only exist if the animation has been run at least once.