Split apart the remainder of fpdf_render_render.cpp into per-class files.

core/include/fpdfdoc/fpdf_doc.h

Index: core/include/fpdfdoc/fpdf_doc.h
diff --git a/core/include/fpdfdoc/fpdf_doc.h b/core/include/fpdfdoc/fpdf_doc.h
index 836b48c17b5ce21dc3a02853bee0de59a686d84f..6ba533160abebe0d1d43f0017a8d461d9c8167eb 100644
--- a/core/include/fpdfdoc/fpdf_doc.h
+++ b/core/include/fpdfdoc/fpdf_doc.h
@@ -11,9 +11,10 @@
 #include <memory>
 #include <vector>
 
-#include "core/include/fpdfapi/fpdf_parser.h"
+#include "core/include/fpdfapi/fpdf_parser_decode.h"
 #include "core/include/fpdfapi/fpdf_render.h"
 
+class CFDF_Document;
 class CFieldTree;
 class CPDF_AAction;
 class CPDF_Action;