Make CPDF_ClipPath have a CPDF_ClipPathData rather than inheriting

core/fpdfapi/fpdf_page/cpdf_pageobject.cpp

 // Copyright 2016 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "core/fpdfapi/fpdf_page/include/cpdf_pageobject.h"
 
 CPDF_PageObject::CPDF_PageObject() {}
 
@@ skipping 63 matching lines @@
   CopyStates(*pSrc);
   m_Left = pSrc->m_Left;
   m_Right = pSrc->m_Right;
   m_Top = pSrc->m_Top;
   m_Bottom = pSrc->m_Bottom;
 }
 
 void CPDF_PageObject::TransformClipPath(CFX_Matrix& matrix) {
   if (!m_ClipPath)
     return;
-  m_ClipPath.GetPrivateCopy();
   m_ClipPath.Transform(matrix);
 }
 
 void CPDF_PageObject::TransformGeneralState(CFX_Matrix& matrix) {
   if (!m_GeneralState)
     return;
   m_GeneralState.GetMutableMatrix()->Concat(matrix);
 }
 
 FX_RECT CPDF_PageObject::GetBBox(const CFX_Matrix* pMatrix) const {
   CFX_FloatRect rect(m_Left, m_Bottom, m_Right, m_Top);
   if (pMatrix) {
     pMatrix->TransformRect(rect);
   }
   return rect.GetOuterRect();
 }