Rename usesOverlayScrollbars of settings to mockScrollbarsUseOverlay

Source/core/testing/Internals.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple 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.
@@ skipping 260 matching lines @@
     PassRefPtr<TypeConversions> typeConversions() const;
 
     Vector<String> getReferencedFilePaths() const;
 
     void startTrackingRepaints(Document*, ExceptionState&);
     void stopTrackingRepaints(Document*, ExceptionState&);
 
     PassRefPtr<ArrayBuffer> serializeObject(PassRefPtr<SerializedScriptValue>) const;
     PassRefPtr<SerializedScriptValue> deserializeBuffer(PassRefPtr<ArrayBuffer>) const;
 
-    void setUsesOverlayScrollbars(bool enabled);
-
     String getCurrentCursorInfo(Document*, ExceptionState&);
 
     String markerTextForListItem(Element*, ExceptionState&);
 
     void forceReload(bool endToEnd);
 
     void enableMockSpeechSynthesizer();
 
     String getImageSourceURL(Element*, ExceptionState&);
 
@@ skipping 14 matching lines @@
     RefPtr<DOMWindow> m_frontendWindow;
     OwnPtr<InspectorFrontendChannelDummy> m_frontendChannel;
     RefPtr<InternalRuntimeFlags> m_runtimeFlags;
     RefPtr<ScrollingCoordinator> m_scrollingCoordinator;
     RefPtr<InternalProfilers> m_profilers;
 };
 
 } // namespace WebCore
 
 #endif