Web Animations: Sort Players in DocumentTimeline::serviceAnimations

Source/core/animation/Player.h

Index: Source/core/animation/Player.h
diff --git a/Source/core/animation/Player.h b/Source/core/animation/Player.h
index bd55fef253f04d3769890a722b570bda6d878e38..c0100177334e0e2ea9a9e1b639d4f8fc83d54db8 100644
--- a/Source/core/animation/Player.h
+++ b/Source/core/animation/Player.h
@@ -96,6 +96,8 @@ public:
     void cancelAnimationOnCompositor();
     bool hasActiveAnimationsOnCompositor();
 
+    static bool hasLowerPriority(Player*, Player*);
+
 private:
     Player(DocumentTimeline&, TimedItem*);
     double sourceEnd() const;
@@ -121,6 +123,8 @@ private:
 
     // This indicates timing information relevant to the player has changed
     bool m_outdated;
+
+    unsigned m_sequenceNumber;
 };
 
 } // namespace