Optimize style recalc when adding @keyframes.

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

Index: third_party/WebKit/Source/core/animation/AnimationTimeline.h
diff --git a/third_party/WebKit/Source/core/animation/AnimationTimeline.h b/third_party/WebKit/Source/core/animation/AnimationTimeline.h
index caddbf3ab950299b0a01d557e7a17e8a0e465086..d01cd06ee52db0127f9aed3734a899aab9595f99 100644
--- a/third_party/WebKit/Source/core/animation/AnimationTimeline.h
+++ b/third_party/WebKit/Source/core/animation/AnimationTimeline.h
@@ -91,6 +91,8 @@ public:
     void clearOutdatedAnimation(Animation*);
     bool hasOutdatedAnimation() const { return m_outdatedAnimationCount > 0; }
     bool needsAnimationTimingUpdate();
+    void setHasUnresolvedKeyframesRule() { m_hasUnresolvedKeyframesRule = true; }
+    void keyframesRulesAdded();
 
     void setPlaybackRate(double);
     double playbackRate() const;
@@ -110,6 +112,7 @@ private:
     Member<Document> m_document;
     double m_zeroTime;
     bool m_zeroTimeInitialized;
+    bool m_hasUnresolvedKeyframesRule;

[alancutter (OOO until 2018), 2016/06/29 03:41:32]

Could this live on Document instead? I don't think CSS specific concepts should
live on the AnimationTimeline.

[alancutter (OOO until 2018), 2016/06/29 08:10:21]

One option to keep it scoped to animations is to make DocumentAnimation a member
of Document and put it in there.

     unsigned m_outdatedAnimationCount;
     // Animations which will be updated on the next frame
     // i.e. current, in effect, or had timing changed