Remove "this==NULL" and adjust corresponding callers

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_TilingPattern::CPDF_TilingPattern(CPDF_Document* pDoc, CPDF_Object* pPatternObj, const CFX_AffineMatrix* parentMatrix) :
     CPDF_Pattern(parentMatrix)
@@ skipping 79 matching lines @@
     }
     m_ShadingType = 0;
     m_pCS = NULL;
     m_nFuncs = 0;
 }
 FX_BOOL CPDF_ShadingPattern::Load()
 {
     if (m_ShadingType != 0) {
         return TRUE;
     }
-    CPDF_Dictionary* pShadingDict = m_pShadingObj->GetDict();
+    CPDF_Dictionary* pShadingDict = m_pShadingObj ? m_pShadingObj->GetDict() : NULL;
     if (pShadingDict == NULL) {
         return FALSE;
     }
     if (m_nFuncs) {
         for (int i = 0; i < m_nFuncs; i ++)
             if (m_pFunctions[i]) {
                 delete m_pFunctions[i];
             }
         m_nFuncs = 0;
     }
@@ skipping 158 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;
 }