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

core/src/fpdfapi/fpdf_font/fpdf_font.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 "core/src/fpdfapi/fpdf_font/font_int.h"
 
+#include "core/include/fpdfapi/cpdf_document.h"
 #include "core/include/fpdfapi/fpdf_module.h"
 #include "core/include/fpdfapi/fpdf_page.h"
 #include "core/include/fpdfapi/fpdf_pageobj.h"
 #include "core/include/fpdfapi/fpdf_resource.h"
 #include "core/include/fxcrt/fx_ext.h"
 #include "core/include/fxge/fx_freetype.h"
 #include "core/src/fpdfapi/fpdf_page/pageint.h"
 #include "third_party/base/stl_util.h"
 
 #if _FXM_PLATFORM_ == _FXM_PLATFORM_APPLE_
@@ skipping 1781 matching lines @@
   return pChar ? pChar->m_BBox : FX_RECT();
 }
 
 CPDF_Type3Char::CPDF_Type3Char(CPDF_Form* pForm)
     : m_pForm(pForm), m_pBitmap(nullptr), m_bColored(FALSE) {}
 
 CPDF_Type3Char::~CPDF_Type3Char() {
   delete m_pForm;
   delete m_pBitmap;
 }