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

core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.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_page/pageint.h"
 
 #include <algorithm>
 
+#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_render.h"
 #include "core/src/fpdfapi/fpdf_render/render_int.h"
 #include "third_party/base/stl_util.h"
 
 namespace {
 
 FX_FLOAT ClipFloat(FX_FLOAT f) {
@@ skipping 664 matching lines @@
       pDict = NULL;
       if (item.GetParamType() == CPDF_ContentMarkItem::PropertiesDict ||
           item.GetParamType() == CPDF_ContentMarkItem::DirectDict) {
         pDict = item.GetParam();
       }
       return TRUE;
     }
   }
   return FALSE;
 }