Adding @keyframes rules only affects TreeScope plus host.

third_party/WebKit/Source/core/animation/AnimationTimeline.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 313 matching lines @@
     for (const auto& animation : m_animations) {
         animation->setCompositorPending(sourceChanged);
     }
 }
 
 double AnimationTimeline::playbackRate() const
 {
     return m_playbackRate;
 }
 
-void AnimationTimeline::invalidateKeyframeEffects()
+void AnimationTimeline::invalidateKeyframeEffects(const TreeScope& treeScope)
 {
     for (const auto& animation : m_animations)
-        animation->invalidateKeyframeEffect();
+        animation->invalidateKeyframeEffect(treeScope);
 }
 
 DEFINE_TRACE(AnimationTimeline)
 {
     visitor->trace(m_document);
     visitor->trace(m_timing);
     visitor->trace(m_animationsNeedingUpdate);
     visitor->trace(m_animations);
 }
 
 } // namespace blink