Remove "this==NULL" and adjust corresponding callers

fpdfsdk/src/fpdf_ext.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/fsdk_define.h"
 #include "../include/fpdf_ext.h"
 
 #define  FPDFSDK_UNSUPPORT_CALL 100
@@ skipping 154 matching lines @@
         {
                 CFX_ByteString cbString;
                 if(pRootDict->KeyExist("Collection"))
                 {
                         FPDF_UnSupportError(FPDF_UNSP_DOC_PORTABLECOLLECTION);
                         return ;
                 }
                 if(pRootDict->KeyExist("Names"))
                 {
                         CPDF_Dictionary* pNameDict = pRootDict->GetDict("Names");
-                        if(pNameDict->KeyExist("EmbeddedFiles"))
+                        if (pNameDict && pNameDict->KeyExist("EmbeddedFiles"))
                         {
                                 FPDF_UnSupportError(FPDF_UNSP_DOC_ATTACHMENT);
                                 return;
                         }
-                        else if(pNameDict->KeyExist("JavaScript"))
+                        else if (pNameDict && pNameDict->KeyExist("JavaScript"))
                         {
                                 CPDF_Dictionary* pJSDict = pNameDict->GetDict("JavaScript");
-                                CPDF_Array * pArray = pJSDict->GetArray("Names");
+                                CPDF_Array * pArray = pJSDict ? pJSDict->GetArray("Names") : NULL;
                                 if (pArray) {
                                         int nCount = pArray->GetCount();
                                         for(int i=0; i<nCount; i++)
                                         {
                                                 CFX_ByteString cbStr = pArray->GetString(i);
                                                 if(cbStr.Compare("com.adobe.acrobat.SharedReview.Register") == 0)
                                                 {
                                                         FPDF_UnSupportError(FPDF_UNSP_DOC_SHAREDREVIEW);
                                                         return;
                                                 }
@@ skipping 42 matching lines @@
                 return PAGEMODE_USETHUMBS;
         else if (strPageMode.EqualNoCase(FX_BSTR("FullScreen")))
                 return PAGEMODE_FULLSCREEN;
         else if (strPageMode.EqualNoCase(FX_BSTR("UseOC")))
                 return PAGEMODE_USEOC;
         else if (strPageMode.EqualNoCase(FX_BSTR("UseAttachments")))
                 return PAGEMODE_USEATTACHMENTS;
 
         return PAGEMODE_UNKNOWN;
 }