Introduce CPDF_Document::FromFPDFDocument().

core/src/fpdfapi/fpdf_parser/fpdf_parser_document.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_parser.h"
 #include "../../../include/fpdfapi/fpdf_module.h"
 
+// static
+CPDF_Document* CPDF_Document::FromFPDFDocument(FPDF_DOCUMENT document) {
+  return static_cast<CPDF_Document*>(document);
+}
+
 CPDF_Document::CPDF_Document(CPDF_Parser* pParser)
     : CPDF_IndirectObjects(pParser) {
   ASSERT(pParser != NULL);
   m_pRootDict = NULL;
   m_pInfoDict = NULL;
   m_bLinearized = FALSE;
   m_dwFirstPageNo = 0;
   m_dwFirstPageObjNum = 0;
   m_pDocPage = CPDF_ModuleMgr::Get()->GetPageModule()->CreateDocData(this);
   m_pDocRender = CPDF_ModuleMgr::Get()->GetRenderModule()->CreateDocData(this);
@@ skipping 336 matching lines @@
 void CPDF_Document::ClearPageData() {
   if (m_pDocPage) {
     CPDF_ModuleMgr::Get()->GetPageModule()->ClearDoc(this);
   }
 }
 void CPDF_Document::ClearRenderData() {
   if (m_pDocRender) {
     CPDF_ModuleMgr::Get()->GetRenderModule()->ClearDocData(m_pDocRender);
   }
 }