Clean up CPDF_Page.

core/fpdfapi/fpdf_page/cpdf_shadingobject.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_shadingobject.h"
 
 #include "core/fpdfapi/fpdf_page/cpdf_shadingpattern.h"
 #include "core/fpdfapi/fpdf_page/pageint.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_document.h"
 
 CPDF_ShadingObject::CPDF_ShadingObject() : m_pShading(nullptr) {}
 
 CPDF_ShadingObject::~CPDF_ShadingObject() {}
 
 CPDF_ShadingObject* CPDF_ShadingObject::Clone() const {
   CPDF_ShadingObject* obj = new CPDF_ShadingObject;
   obj->CopyData(this);
 
   obj->m_pShading = m_pShading;
-  if (obj->m_pShading && obj->m_pShading->m_pDocument) {
-    CPDF_DocPageData* pDocPageData =
-        obj->m_pShading->m_pDocument->GetPageData();
-    obj->m_pShading = (CPDF_ShadingPattern*)pDocPageData->GetPattern(
+  if (obj->m_pShading && obj->m_pShading->document()) {
+    CPDF_DocPageData* pDocPageData = obj->m_pShading->document()->GetPageData();
+    CPDF_Pattern* pattern = pDocPageData->GetPattern(
         obj->m_pShading->m_pShadingObj, m_pShading->m_bShadingObj,
-        &obj->m_pShading->m_ParentMatrix);
+        obj->m_pShading->parent_matrix());
+    obj->m_pShading = pattern ? pattern->AsShadingPattern() : nullptr;
   }
   obj->m_Matrix = m_Matrix;
   return obj;
 }
 
 void CPDF_ShadingObject::Transform(const CFX_Matrix& matrix) {
   if (!m_ClipPath.IsNull()) {
     m_ClipPath.GetModify();
     m_ClipPath.Transform(matrix);
   }
   m_Matrix.Concat(matrix);
   if (!m_ClipPath.IsNull()) {
     CalcBoundingBox();
   } else {
     matrix.TransformRect(m_Left, m_Right, m_Top, m_Bottom);
   }
 }
 
 void CPDF_ShadingObject::CalcBoundingBox() {
   if (m_ClipPath.IsNull()) {
     return;
   }
   CFX_FloatRect rect = m_ClipPath.GetClipBox();
   m_Left = rect.left;
   m_Bottom = rect.bottom;
   m_Right = rect.right;
   m_Top = rect.top;
 }