Web Animations: Fix CSS events to handle animations with very short durations

Source/core/animation/TimedItem.h

Index: Source/core/animation/TimedItem.h
diff --git a/Source/core/animation/TimedItem.h b/Source/core/animation/TimedItem.h
index 93b79a7fc7b9503257f36bbed398dab0249c2b72..0aae5cad13eefe257434bcfe0fa133569b004761 100644
--- a/Source/core/animation/TimedItem.h
+++ b/Source/core/animation/TimedItem.h
@@ -52,7 +52,7 @@ static inline double nullValue()
 class TimedItemEventDelegate {
 public:
     virtual ~TimedItemEventDelegate() { };
-    virtual void onEventCondition(bool wasInPlay, bool isInPlay, double previousIteration, double currentIteration) = 0;
+    virtual void onEventCondition(bool wasInPlay, bool isInPlay, bool wasCurrent, bool isCurrent, double previousIteration, double currentIteration) = 0;
 };
 
 class TimedItem : public RefCounted<TimedItem> {
@@ -107,7 +107,6 @@ private:
 
     // FIXME: Should be versioned by monotonic value on player.
     mutable struct CalculatedTiming {
-        CalculatedTiming();
         double activeDuration;
         double currentIteration;
         double timeFraction;
@@ -115,6 +114,7 @@ private:
         bool isInEffect;
         bool isInPlay;
     } m_calculated;
+    mutable bool m_isFirstSample;
 
     // FIXME: Should check the version and reinherit time if inconsistent.
     const CalculatedTiming& ensureCalculated() const { return m_calculated; }