Adding @keyframes rules only affects TreeScope plus host.

third_party/WebKit/Source/core/dom/StyleEngine.cpp

Index: third_party/WebKit/Source/core/dom/StyleEngine.cpp
diff --git a/third_party/WebKit/Source/core/dom/StyleEngine.cpp b/third_party/WebKit/Source/core/dom/StyleEngine.cpp
index c19ca69998809a5f109748fc23b99429542a7d63..5971555191e67bebdedb2b49b5bde9631c42880b 100644
--- a/third_party/WebKit/Source/core/dom/StyleEngine.cpp
+++ b/third_party/WebKit/Source/core/dom/StyleEngine.cpp
@@ -28,7 +28,6 @@
 #include "core/dom/StyleEngine.h"
 
 #include "core/HTMLNames.h"
-#include "core/animation/DocumentTimeline.h"
 #include "core/css/CSSDefaultStyleSheets.h"
 #include "core/css/CSSFontSelector.h"
 #include "core/css/CSSStyleSheet.h"
@@ -879,17 +878,6 @@ void StyleEngine::ensureFullscreenUAStyle()
         m_resolver->resetRuleFeatures();
 }
 
-void StyleEngine::keyframesRulesAdded()
-{
-    if (m_hasUnresolvedKeyframesRule) {
-        m_hasUnresolvedKeyframesRule = false;
-        document().setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::StyleSheetChange));
-        return;
-    }
-
-    document().timeline().invalidateKeyframeEffects();
-}
-
 DEFINE_TRACE(StyleEngine)
 {
     visitor->trace(m_document);