When forcing clear page data, no need to release colorspace when releasing pattern

core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp

 // Copyright 2014 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 "../../../include/fpdfapi/fpdf_page.h"
 #include "pageint.h"
 
 CPDF_Pattern::CPDF_Pattern(const CFX_AffineMatrix* pParentMatrix) :
-    m_pPatternObj(NULL), m_PatternType(PATTERN_TILING), m_pDocument(NULL)
+    m_pPatternObj(NULL), m_PatternType(PATTERN_TILING), m_pDocument(NULL), m_bForceClear(FALSE)
 {
     if (pParentMatrix) {
         m_ParentMatrix = *pParentMatrix;
     }
 }
 CPDF_Pattern::~CPDF_Pattern()
 {
 }
 CPDF_TilingPattern::CPDF_TilingPattern(CPDF_Document* pDoc, CPDF_Object* pPatternObj, const CFX_AffineMatrix* parentMatrix) :
     CPDF_Pattern(parentMatrix)
@@ skipping 68 matching lines @@
 }
 void CPDF_ShadingPattern::Clear()
 {
     for (int i = 0; i < m_nFuncs; i ++) {
         if (m_pFunctions[i]) {
             delete m_pFunctions[i];
         }
         m_pFunctions[i] = NULL;
     }
     CPDF_ColorSpace* pCS = m_pCS;
-    if (pCS && m_pDocument) {
+    if (!m_bForceClear && pCS && m_pDocument) {
         m_pDocument->GetPageData()->ReleaseColorSpace(pCS->GetArray());
     }
     m_ShadingType = 0;
     m_pCS = NULL;
     m_nFuncs = 0;
 }
 FX_BOOL CPDF_ShadingPattern::Load()
 {
     if (m_ShadingType != 0) {
         return TRUE;
@@ skipping 170 matching lines @@
             }
         }
         stream.m_BitStream.SkipBits(stream.m_nComps * stream.m_nCompBits * color_count);
         if (bGouraud) {
             stream.m_BitStream.ByteAlign();
         }
     }
     rect.Transform(pMatrix);
     return rect;
 }