Separate VTTCue from VTTCueBox and LayoutVTTCue

Source/core/html/track/vtt/VTTCue.h

 /*
  * Copyright (c) 2013, Opera Software ASA. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 29 matching lines @@
 class ExecutionContext;
 class VTTCue;
 class VTTScanner;
 
 struct VTTDisplayParameters {
     VTTDisplayParameters();
 
     FloatPoint position;
     float size;
     CSSValueID direction;
+    CSSValueID textAlign;
     CSSValueID writingMode;
+    float snapToLinesPosition;
 };
 
 class VTTCueBox final : public HTMLDivElement {
 public:
-    static PassRefPtrWillBeRawPtr<VTTCueBox> create(Document& document, VTTCue* cue)
+    static PassRefPtrWillBeRawPtr<VTTCueBox> create(Document& document)
     {
-        return adoptRefWillBeNoop(new VTTCueBox(document, cue));
+        return adoptRefWillBeNoop(new VTTCueBox(document));
     }
 
-    VTTCue* getCue() const { return m_cue; }
     void applyCSSProperties(const VTTDisplayParameters&);
 
-    DECLARE_VIRTUAL_TRACE();
-
 private:
-    VTTCueBox(Document&, VTTCue*);
+    explicit VTTCueBox(Document&);
 
     LayoutObject* createLayoutObject(const ComputedStyle&) override;
 
-    RawPtrWillBeMember<VTTCue> m_cue;
+    // The computed line position for snap-to-lines layout, and NaN for
+    // non-snap-to-lines layout where no adjustment should take place.
+    // This is set in applyCSSProperties and propagated to LayoutVTTCue.
+    float m_snapToLinesPosition;
 };
 
 class VTTCue final : public TextTrackCue {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<VTTCue> create(Document& document, double startTime, double endTime, const String& text)
     {
         return adoptRefWillBeNoop(new VTTCue(document, startTime, endTime, text));
     }
 
@@ skipping 109 matching lines @@
     bool m_snapToLines : 1;
     bool m_displayTreeShouldChange : 1;
 };
 
 // VTTCue is currently the only TextTrackCue subclass.
 DEFINE_TYPE_CASTS(VTTCue, TextTrackCue, cue, true, true);
 
 } // namespace blink
 
 #endif // VTTCue_h