Remove m_margins member from FrameView

Source/core/rendering/RenderPart.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2006, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 16 matching lines @@
 
 namespace WebCore {
 
 // Renderer for frames via RenderFrame and RenderIFrame, and plug-ins via RenderEmbeddedObject.
 class RenderPart : public RenderWidget {
 public:
     explicit RenderPart(Element*);
     virtual ~RenderPart();
 
     virtual void setWidget(PassRefPtr<Widget>) OVERRIDE FINAL;
-    virtual void viewCleared();
 
     bool requiresAcceleratedCompositing() const;
 
     virtual bool needsPreferredWidthsRecalculation() const OVERRIDE FINAL;
     virtual RenderBox* embeddedContentBox() const OVERRIDE FINAL;
 
     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction) OVERRIDE;
 
 protected:
     virtual LayerType layerTypeRequired() const OVERRIDE;
 
 private:
     virtual bool isRenderPart() const OVERRIDE FINAL { return true; }
     virtual const char* renderName() const OVERRIDE { return "RenderPart"; }
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderPart, isRenderPart());
 
 }
 
 #endif