Create compositor animations for effect animations in SPv2.

third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp
index 9587807e9e6e8c90989c9ba6d3b857e07911299e..f285365d6d63eb8a7e526df90789e78222389ec5 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositingReasonFinder.cpp
@@ -178,6 +178,19 @@ bool CompositingReasonFinder::requiresCompositingForAnimation(
   return style.shouldCompositeForCurrentAnimations();
 }
 
+bool CompositingReasonFinder::requiresCompositingForEffectAnimation(
+    const ComputedStyle& style) {
+  if (style.subtreeWillChangeContents()) {
+    return style.isRunningOpacityAnimationOnCompositor() ||
+           style.isRunningFilterAnimationOnCompositor() ||
+           style.isRunningBackdropFilterAnimationOnCompositor();
+  }
+
+  return style.hasCurrentOpacityAnimation() ||
+         style.hasCurrentFilterAnimation() ||
+         style.hasCurrentBackdropFilterAnimation();
+}
+
 bool CompositingReasonFinder::requiresCompositingForTransformAnimation(
     const ComputedStyle& style) {
   return style.subtreeWillChangeContents()