Make code compile with clang_use_chrome_plugin (part I)

core/fpdfapi/fpdf_page/cpdf_shadingpattern.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/cpdf_shadingpattern.h"
 
 #include "core/fpdfapi/fpdf_page/pageint.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
@@ skipping 32 matching lines @@
     m_Pattern2Form.Concat(parentMatrix);
   }
 }
 
 CPDF_ShadingPattern::~CPDF_ShadingPattern() {
   CPDF_ColorSpace* pCS = m_pCountedCS ? m_pCountedCS->get() : nullptr;
   if (pCS && m_pDocument)
     m_pDocument->GetPageData()->ReleaseColorSpace(pCS->GetArray());
 }
 
+CPDF_TilingPattern* CPDF_ShadingPattern::AsTilingPattern() {
+  return nullptr;
+}
+
+CPDF_ShadingPattern* CPDF_ShadingPattern::AsShadingPattern() {
+  return this;
+}
+
 bool CPDF_ShadingPattern::Load() {
   if (m_ShadingType != kInvalidShading)
     return TRUE;
 
   CPDF_Dictionary* pShadingDict =
       m_pShadingObj ? m_pShadingObj->GetDict() : nullptr;
   if (!pShadingDict)
     return FALSE;
 
   m_pFunctions.clear();
@@ skipping 17 matching lines @@
     m_pCountedCS = pDocPageData->FindColorSpacePtr(m_pCS->GetArray());
 
   m_ShadingType = ToShadingType(pShadingDict->GetIntegerBy("ShadingType"));
 
   // We expect to have a stream if our shading type is a mesh.
   if (IsMeshShading() && !ToStream(m_pShadingObj))
     return FALSE;
 
   return TRUE;
 }