Split xfa_document_serialize into class files

xfa.gyp

 {
   "variables": {
     "chromium_code": 1,
     "pdf_enable_v8%": 1,
      "variables": {
       'clang_use_chrome_plugins': 1,
     },
   },
   "target_defaults": {
     "defines": [
@@ skipping 457 matching lines @@
         "xfa/fxfa/parser/cxfa_calculate.h",
         "xfa/fxfa/parser/cxfa_caption.cpp",
         "xfa/fxfa/parser/cxfa_caption.h",
         "xfa/fxfa/parser/cxfa_corner.h",
         "xfa/fxfa/parser/cxfa_containerlayoutitem.cpp",
         "xfa/fxfa/parser/cxfa_containerlayoutitem.h",
         "xfa/fxfa/parser/cxfa_contentlayoutitem.cpp",
         "xfa/fxfa/parser/cxfa_contentlayoutitem.h",
         "xfa/fxfa/parser/cxfa_data.cpp",
         "xfa/fxfa/parser/cxfa_data.h",
+        "xfa/fxfa/parser/cxfa_dataexporter.cpp",
+        "xfa/fxfa/parser/cxfa_dataexporter.h",
+        "xfa/fxfa/parser/cxfa_dataimporter.cpp",
+        "xfa/fxfa/parser/cxfa_dataimporter.h",
         "xfa/fxfa/parser/cxfa_document.cpp",
         "xfa/fxfa/parser/cxfa_document.h",
         "xfa/fxfa/parser/cxfa_document_parser.cpp",
         "xfa/fxfa/parser/cxfa_document_parser.h",
         "xfa/fxfa/parser/cxfa_edge.h",
         "xfa/fxfa/parser/cxfa_event.cpp",
         "xfa/fxfa/parser/cxfa_event.h",
         "xfa/fxfa/parser/cxfa_exdata.cpp",
         "xfa/fxfa/parser/cxfa_exdata.h",
         "xfa/fxfa/parser/cxfa_fill.cpp",
@@ skipping 55 matching lines @@
         "xfa/fxfa/parser/xfa_basic_data.cpp",
         "xfa/fxfa/parser/xfa_basic_data_attributes.cpp",
         "xfa/fxfa/parser/xfa_basic_data_element_attributes.cpp",
         "xfa/fxfa/parser/xfa_basic_data_element_properties.cpp",
         "xfa/fxfa/parser/xfa_basic_data_element_script.cpp",
         "xfa/fxfa/parser/xfa_basic_data_enum.cpp",
         "xfa/fxfa/parser/xfa_basic_data_packets.cpp",
         "xfa/fxfa/parser/xfa_basic_data.h",
         "xfa/fxfa/parser/xfa_document_datamerger_imp.cpp",
         "xfa/fxfa/parser/xfa_document_datamerger_imp.h",
-        "xfa/fxfa/parser/xfa_document_serialize.cpp",
-        "xfa/fxfa/parser/xfa_document_serialize.h",
         "xfa/fxfa/parser/xfa_layout_appadapter.cpp",
         "xfa/fxfa/parser/xfa_layout_appadapter.h",
         "xfa/fxfa/parser/xfa_layout_itemlayout.cpp",
         "xfa/fxfa/parser/xfa_layout_itemlayout.h",
         "xfa/fxfa/parser/xfa_layout_pagemgr_new.cpp",
         "xfa/fxfa/parser/xfa_layout_pagemgr_new.h",
         "xfa/fxfa/parser/xfa_locale.cpp",
         "xfa/fxfa/parser/xfa_locale.h",
         "xfa/fxfa/parser/xfa_localemgr.cpp",
         "xfa/fxfa/parser/xfa_localemgr.h",
@@ skipping 44 matching lines @@
           "sources": [],
         }],
         ["OS == 'mac'", {
           "configurations": {},
           "sources": [],
         }],
       ]
     }
   ]
 }