Remove IXFA_Parser, cleanup XFA parser code.

xfa.gyp

 {
   "variables": {
     "chromium_code": 1,
     "pdf_enable_v8%": 1,
   },
   "target_defaults": {
     "defines": [
       "PDF_ENABLE_XFA",
     ],
     'msvs_disabled_warnings': [
@@ skipping 520 matching lines @@
         "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",
         "xfa/fxfa/parser/xfa_localevalue.cpp",
         "xfa/fxfa/parser/xfa_localevalue.h",
         "xfa/fxfa/parser/xfa_object.h",
         "xfa/fxfa/parser/xfa_object_imp.cpp",
-        "xfa/fxfa/parser/xfa_parser.h",
         "xfa/fxfa/parser/xfa_parser_imp.cpp",
         "xfa/fxfa/parser/xfa_parser_imp.h",
         "xfa/fxfa/parser/xfa_script.h",
         "xfa/fxfa/parser/xfa_script_datawindow.cpp",
         "xfa/fxfa/parser/xfa_script_datawindow.h",
         "xfa/fxfa/parser/xfa_script_eventpseudomodel.cpp",
         "xfa/fxfa/parser/xfa_script_eventpseudomodel.h",
         "xfa/fxfa/parser/xfa_script_hostpseudomodel.cpp",
         "xfa/fxfa/parser/xfa_script_hostpseudomodel.h",
         "xfa/fxfa/parser/xfa_script_imp.cpp",
@@ skipping 51 matching lines @@
           "sources": [],
         }],
         ["OS == 'mac'", {
           "configurations": {},
           "sources": [],
         }],
       ]
     }
   ]
 }