Make RenderObject::style() return a const object

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 47 matching lines @@
     }
 
     VTTCue* getCue() const { return m_cue; }
     void applyCSSProperties(const VTTDisplayParameters&);
 
     virtual void trace(Visitor*) override;
 
 private:
     VTTCueBox(Document&, VTTCue*);
 
-    virtual RenderObject* createRenderer(RenderStyle*) override;
+    virtual RenderObject* createRenderer(const RenderStyle*) override;
 
     RawPtrWillBeMember<VTTCue> m_cue;
 };
 
 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 113 matching lines @@
     bool m_displayTreeShouldChange : 1;
     bool m_notifyRegion : 1;
 };
 
 // VTTCue is currently the only TextTrackCue subclass.
 DEFINE_TYPE_CASTS(VTTCue, TextTrackCue, cue, true, true);
 
 } // namespace blink
 
 #endif // VTTCue_h