Make DisplayItemClient an interface

third_party/WebKit/Source/platform/scroll/ScrollbarThemeClient.h

 /*
  * Copyright (C) 2012 Google Inc. 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
@@ skipping 21 matching lines @@
 #include "platform/geometry/IntSize.h"
 #include "platform/graphics/paint/DisplayItemClient.h"
 #include "platform/scroll/ScrollTypes.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class Widget;
 
-class PLATFORM_EXPORT ScrollbarThemeClient {
+class PLATFORM_EXPORT ScrollbarThemeClient : public DisplayItemClient {
 public:
     virtual int x() const = 0;
     virtual int y() const = 0;
     virtual int width() const = 0;
     virtual int height() const = 0;
     virtual IntSize size() const = 0;
     virtual IntPoint location() const = 0;
 
     virtual Widget* parent() const = 0;
     virtual Widget* root() const = 0;
@@ skipping 36 matching lines @@
     virtual void setIsAlphaLocked(bool) = 0;
 
     virtual float elasticOverscroll() const = 0;
     virtual void setElasticOverscroll(float) = 0;
 
     virtual bool trackNeedsRepaint() const = 0;
     virtual void setTrackNeedsRepaint(bool) = 0;
     virtual bool thumbNeedsRepaint() const = 0;
     virtual void setThumbNeedsRepaint(bool) = 0;
 
-    virtual DisplayItemClient displayItemClient() const = 0;
-    virtual String debugName() const = 0;
-
 protected:
     virtual ~ScrollbarThemeClient() { }
 };
 
 } // namespace blink
 
 #endif // ScollbarThemeClient_h