Basic ScrollTimeline implementation for Animation Worklet

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

 /*
  * 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 65 matching lines @@
   Animation* Play(AnimationEffectReadOnly*);
   HeapVector<Member<Animation>> getAnimations();
 
   void AnimationAttached(Animation&);
 
   bool IsActive();
   bool HasPendingUpdates() const {
     return !animations_needing_update_.IsEmpty();
   }
   double ZeroTime();
-  double currentTime(bool& is_null);
-  double currentTime();
-  double CurrentTimeInternal(bool& is_null);
-  double CurrentTimeInternal();
+  virtual double currentTime(bool& is_null);
+  virtual double currentTime();
+  virtual double CurrentTimeInternal(bool& is_null);
+  virtual double CurrentTimeInternal();
   void setCurrentTime(double, bool is_null);
   void SetCurrentTimeInternal(double);
   double EffectiveTime();
   void PauseAnimationsForTesting(double);
 
   void SetAllCompositorPending(bool source_changed = false);
   void SetOutdatedAnimation(Animation*);
   void ClearOutdatedAnimation(Animation*);
   bool HasOutdatedAnimation() const { return outdated_animation_count_ > 0; }
   bool NeedsAnimationTimingUpdate();
   void InvalidateKeyframeEffects(const TreeScope&);
 
   void SetPlaybackRate(double);
   double PlaybackRate() const;
 
   CompositorAnimationTimeline* CompositorTimeline() const {
     return compositor_timeline_.get();
   }
 
   Document* GetDocument() { return document_.Get(); }
   void Wake();
   void ResetForTesting();
 
-  DECLARE_TRACE();
+  DECLARE_VIRTUAL_TRACE();
 
  protected:
   AnimationTimeline(Document*, PlatformTiming*);
 
  private:
   Member<Document> document_;
   double zero_time_;
   bool zero_time_initialized_;
   unsigned outdated_animation_count_;
   // Animations which will be updated on the next frame
@@ skipping 33 matching lines @@
     Member<AnimationTimeline> timeline_;
     TaskRunnerTimer<AnimationTimelineTiming> timer_;
   };
 
   friend class AnimationAnimationTimelineTest;
 };
 
 }  // namespace blink
 
 #endif