Web Animations: Don't compare start time for AnimationPlayer sorting

Source/core/animation/AnimationPlayer.h

Index: Source/core/animation/AnimationPlayer.h
diff --git a/Source/core/animation/AnimationPlayer.h b/Source/core/animation/AnimationPlayer.h
index 4825c26a566478019fe7e01d82ebbcf82e039616..6efd5c7cb33aadb7445c4fc4ffd98a44bd127d8a 100644
--- a/Source/core/animation/AnimationPlayer.h
+++ b/Source/core/animation/AnimationPlayer.h
@@ -126,20 +126,16 @@ public:
     class SortInfo {
     public:
         friend class AnimationPlayer;
-        bool operator<(const SortInfo& other) const;
-        double startTime() const { return m_startTime; }
-        bool hasLowerSequenceNumber(const SortInfo& other) const
+        bool operator<(const SortInfo& other) const
         {
             return m_sequenceNumber < other.m_sequenceNumber;
         }
     private:
-        SortInfo(unsigned sequenceNumber, double startTime)
+        SortInfo(unsigned sequenceNumber)
             : m_sequenceNumber(sequenceNumber)
-            , m_startTime(startTime)
         {
         }
         unsigned m_sequenceNumber;
-        double m_startTime;
     };
 
     const SortInfo& sortInfo() const { return m_sortInfo; }