Simplify PDFium by removing code that's not used in the open source repo.

pdfium.gyp

 {
   'variables': {
     'pdf_use_skia%': 0,
   },
   'target_defaults': {
     'defines' : [
-      'FOXIT_CHROME_BUILD',
       '_FXFT_VERSION_=2501',
       '_FPDFSDK_LIB',
       '_NO_GDIPLUS_',  # workaround text rendering issues on Windows
       'OPJ_STATIC',
     ],
     'conditions': [
       ['pdf_use_skia==1', {
         'defines': ['_SKIA_SUPPORT_'],
       }],
       ['OS=="linux"', {
@@ skipping 30 matching lines @@
         'fxge',
         'javascript',
         'jsapi',
         'pdfwindow',
       ],
       'ldflags': [ '-L<(PRODUCT_DIR)',],
       'sources': [
         'fpdfsdk/include/fpdfdoc.h',
         'fpdfsdk/include/fpdfedit.h',
         'fpdfsdk/include/fpdfformfill.h',
-        'fpdfsdk/include/fpdfoom.h',
         'fpdfsdk/include/fpdftext.h',
         'fpdfsdk/include/fpdfview.h',
         'fpdfsdk/include/fpdf_dataavail.h',
         'fpdfsdk/include/fpdf_flatten.h',
         'fpdfsdk/include/fpdf_progressive.h',
         'fpdfsdk/include/fpdf_searchex.h',
         'fpdfsdk/include/fpdf_sysfontinfo.h',
         'fpdfsdk/include/fpdf_ext.h',
         'fpdfsdk/include/fpdf_sysfontinfo.h',
         'fpdfsdk/include/fsdk_actionhandler.h',
         'fpdfsdk/include/fsdk_annothandler.h',
         'fpdfsdk/include/fsdk_baseannot.h',
         'fpdfsdk/include/fsdk_baseform.h',
         'fpdfsdk/src/fpdfdoc.cpp',
         'fpdfsdk/src/fpdfeditimg.cpp',
         'fpdfsdk/src/fpdfeditpage.cpp',
         'fpdfsdk/src/fpdfformfill.cpp',
-        'fpdfsdk/src/fpdfoom.cpp',
         'fpdfsdk/src/fpdfppo.cpp',
         'fpdfsdk/src/fpdfsave.cpp',
         'fpdfsdk/src/fpdftext.cpp',
         'fpdfsdk/src/fpdfview.cpp',
         'fpdfsdk/src/fpdf_dataavail.cpp',
         'fpdfsdk/src/fpdf_ext.cpp',
         'fpdfsdk/src/fpdf_flatten.cpp',
         'fpdfsdk/src/fpdf_progressive.cpp',
         'fpdfsdk/src/fpdf_searchex.cpp',
         'fpdfsdk/src/fpdf_sysfontinfo.cpp',
@@ skipping 199 matching lines @@
         'core/src/fpdfapi/fpdf_font/fpdf_font_utility.cpp',
         'core/src/fpdfapi/fpdf_font/ttgsubtable.cpp',
         'core/src/fpdfapi/fpdf_font/ttgsubtable.h',
         'core/src/fpdfapi/fpdf_page/fpdf_page.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_colors.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_doc.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_func.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_graph_state.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_image.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_parser.cpp',
-        'core/src/fpdfapi/fpdf_page/fpdf_page_parser_new.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_path.cpp',
         'core/src/fpdfapi/fpdf_page/fpdf_page_pattern.cpp',
         'core/src/fpdfapi/fpdf_page/pageint.h',
         'core/src/fpdfapi/fpdf_parser/filters_int.h',
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_decode.cpp',
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_document.cpp',
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_encrypt.cpp',
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_fdf.cpp',
         'core/src/fpdfapi/fpdf_parser/fpdf_parser_filters.cpp',
@@ skipping 334 matching lines @@
         'core/src/fxge/fx_freetype/src/fxft_raster.c',
         'core/src/fxge/fx_freetype/src/fxft_sfnt.c',
         'core/src/fxge/fx_freetype/src/fxft_smooth.c',
         'core/src/fxge/fx_freetype/src/fxft_truetype.c',
         'core/src/fxge/fx_freetype/src/fxft_type1.c',
         'core/src/fxge/fx_freetype/src/fxft_type1cid.c',
         'core/src/fxge/ge/fx_ge.cpp',
         'core/src/fxge/ge/fx_ge_device.cpp',
         'core/src/fxge/ge/fx_ge_font.cpp',
         'core/src/fxge/ge/fx_ge_fontmap.cpp',
-        'core/src/fxge/ge/fx_ge_linux.cpp',
         'core/src/fxge/ge/fx_ge_path.cpp',
         'core/src/fxge/ge/fx_ge_ps.cpp',
         'core/src/fxge/ge/fx_ge_text.cpp',
         'core/src/fxge/ge/text_int.h',
       ],
       'conditions': [
         ['pdf_use_skia==1', {
           'sources': [
             'core/src/fxge/skia/fx_skia_blitter_new.cpp',
             'core/src/fxge/skia/fx_skia_device.cpp',
@@ skipping 191 matching lines @@
         'fpdfsdk/src/formfiller/FFL_ListBox.cpp',
         'fpdfsdk/src/formfiller/FFL_Notify.cpp',
         'fpdfsdk/src/formfiller/FFL_PushButton.cpp',
         'fpdfsdk/src/formfiller/FFL_RadioButton.cpp',
         'fpdfsdk/src/formfiller/FFL_TextField.cpp',
         'fpdfsdk/src/formfiller/FFL_Utils.cpp',
       ],
     },
   ],
 }