Split off CPDF_Document into its own .cpp/.h files.

fpdfsdk/src/fpdf_dataavail.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 "public/fpdf_dataavail.h"
 
+#include "core/include/fpdfapi/cpdf_document.h"
 #include "fpdfsdk/include/fsdk_define.h"
 #include "public/fpdf_formfill.h"
 
 // These checks are here because core/ and public/ cannot depend on each other.
 static_assert(IPDF_DataAvail::DataError == PDF_DATA_ERROR,
               "IPDF_DataAvail::DataError value mismatch");
 static_assert(IPDF_DataAvail::DataNotAvailable == PDF_DATA_NOTAVAIL,
               "IPDF_DataAvail::DataNotAvailable value mismatch");
 static_assert(IPDF_DataAvail::DataAvailable == PDF_DATA_AVAIL,
               "IPDF_DataAvail::DataAvailable value mismatch");
@@ skipping 142 matching lines @@
     return PDF_FORM_ERROR;
   CFPDF_DownloadHintsWrap hints_wrap(hints);
   return ((CFPDF_DataAvail*)avail)->m_pDataAvail->IsFormAvail(&hints_wrap);
 }
 
 DLLEXPORT int STDCALL FPDFAvail_IsLinearized(FPDF_AVAIL avail) {
   if (!avail)
     return PDF_LINEARIZATION_UNKNOWN;
   return ((CFPDF_DataAvail*)avail)->m_pDataAvail->IsLinearizedPDF();
 }