Remove XFA_HFM2JSCONTEXT.

xfa.gyp

 {
   "variables": {
     "chromium_code": 1,
     "pdf_enable_v8%": 1,
   },
   "target_defaults": {
     "defines": [
       "PDF_ENABLE_XFA",
     ],
     'msvs_disabled_warnings': [
@@ skipping 543 matching lines @@
         "xfa/fxfa/app/xfa_fwladapter.h",
         "xfa/fxfa/app/xfa_fwltheme.cpp",
         "xfa/fxfa/app/xfa_fwltheme.h",
         "xfa/fxfa/app/xfa_rendercontext.cpp",
         "xfa/fxfa/app/xfa_textlayout.cpp",
         "xfa/fxfa/app/xfa_textlayout.h",
         "xfa/fxfa/fm2js/xfa_error.cpp",
         "xfa/fxfa/fm2js/xfa_error.h",
         "xfa/fxfa/fm2js/xfa_expression.cpp",
         "xfa/fxfa/fm2js/xfa_expression.h",
-        "xfa/fxfa/fm2js/xfa_fm2jsapi.cpp",
-        "xfa/fxfa/fm2js/xfa_fm2jsapi.h",
         "xfa/fxfa/fm2js/xfa_fm2jscontext.cpp",
         "xfa/fxfa/fm2js/xfa_fm2jscontext.h",
         "xfa/fxfa/fm2js/xfa_fmparse.cpp",
         "xfa/fxfa/fm2js/xfa_fmparse.h",
         "xfa/fxfa/fm2js/xfa_lexer.cpp",
         "xfa/fxfa/fm2js/xfa_lexer.h",
         "xfa/fxfa/fm2js/xfa_program.cpp",
         "xfa/fxfa/fm2js/xfa_program.h",
         "xfa/fxfa/fm2js/xfa_simpleexpression.cpp",
         "xfa/fxfa/fm2js/xfa_simpleexpression.h",
@@ skipping 172 matching lines @@
           "sources": [],
         }],
         ["OS == 'mac'", {
           "configurations": {},
           "sources": [],
         }],
       ]
     }
   ]
 }