Remove internal uses of TrackDisplayUpdateScope in CueTimeline

Source/core/html/track/CueTimeline.h

Index: Source/core/html/track/CueTimeline.h
diff --git a/Source/core/html/track/CueTimeline.h b/Source/core/html/track/CueTimeline.h
index 52d44db03b2fbf11a6eaf9e209a270cc77d92d70..2437cfa648eb0f4f538e8f3e1d04b1e27377e61c 100644
--- a/Source/core/html/track/CueTimeline.h
+++ b/Source/core/html/track/CueTimeline.h
@@ -44,6 +44,9 @@ public:
 private:
     HTMLMediaElement& mediaElement() const { return *m_mediaElement; }
 
+    void addCueInternal(PassRefPtrWillBeRawPtr<TextTrackCue>);
+    void removeCueInternal(PassRefPtrWillBeRawPtr<TextTrackCue>);
+
     RawPtrWillBeMember<HTMLMediaElement> m_mediaElement;
 
     CueIntervalTree m_cueTree;