Fixup page removal for XFA documents.

fpdfsdk/fpdfxfa/fpdfxfa_doc.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 "fpdfsdk/fpdfxfa/include/fpdfxfa_doc.h"
 
 #include "core/fpdfapi/fpdf_parser/include/cpdf_array.h"
 #include "core/fpdfapi/fpdf_parser/include/cpdf_document.h"
@@ skipping 136 matching lines @@
       if (m_pXFADoc)
         return m_pXFADocView->CountPageViews();
     default:
       return 0;
   }
 }
 
 CPDFXFA_Page* CPDFXFA_Document::GetPage(int page_index) {
   if (page_index < 0)
     return nullptr;
+
   CPDFXFA_Page* pPage = nullptr;
   int nCount = m_XFAPageList.GetSize();
   if (nCount > 0 && page_index < nCount) {
     pPage = m_XFAPageList.GetAt(page_index);
     if (pPage)
       pPage->AddRef();
   } else {
     m_nPageCount = GetPageCount();
     m_XFAPageList.SetSize(m_nPageCount);
   }
   if (pPage)
     return pPage;
+
   pPage = new CPDFXFA_Page(this, page_index);
   if (!pPage->LoadPage()) {
     pPage->Release();
     return nullptr;
   }
   m_XFAPageList.SetAt(page_index, pPage);
   return pPage;
 }
 
 CPDFXFA_Page* CPDFXFA_Document::GetPage(CXFA_FFPageView* pPage) {
   if (!pPage)
-    return NULL;
+    return nullptr;
 
   if (!m_pXFADoc)
-    return NULL;
+    return nullptr;
 
   if (m_iDocType != DOCTYPE_DYNAMIC_XFA)
-    return NULL;
+    return nullptr;
 
   int nSize = m_XFAPageList.GetSize();
   for (int i = 0; i < nSize; i++) {
     CPDFXFA_Page* pTempPage = m_XFAPageList.GetAt(i);
     if (!pTempPage)
       continue;
     if (pTempPage->GetXFAPageView() && pTempPage->GetXFAPageView() == pPage)
       return pTempPage;
   }
 
-  return NULL;
+  return nullptr;
 }
 
 void CPDFXFA_Document::DeletePage(int page_index) {
+  // Delete from the document first because, if GetPage was never called for
+  // this |page_index| then |m_XFAPageList| may have size < |page_index| even
+  // if it's a valid page in the document.
+  if (m_pPDFDoc)
+    m_pPDFDoc->DeletePage(page_index);
+
   if (page_index < 0 || page_index >= m_XFAPageList.GetSize())
     return;
 
   if (CPDFXFA_Page* pPage = m_XFAPageList.GetAt(page_index))
     pPage->Release();
 }
 
 void CPDFXFA_Document::RemovePage(CPDFXFA_Page* page) {
   m_XFAPageList.SetAt(page->GetPageIndex(), NULL);
 }
@@ skipping 1057 matching lines @@
   }
 
   return _GetHValueByName(szPropName, hValue,
                           m_pSDKDoc->GetEnv()->GetJSRuntime());
 }
 FX_BOOL CPDFXFA_Document::_GetHValueByName(const CFX_ByteStringC& utf8Name,
                                            FXJSE_HVALUE hValue,
                                            IJS_Runtime* runTime) {
   return runTime->GetHValueByName(utf8Name, hValue);
 }