Remove the document tagged code as it is unused.

pdfium.gyp

 # Copyright 2015 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'chromium_code': 1,
     'pdf_use_skia%': 0,
     'pdf_enable_v8%': 1,
     'pdf_enable_xfa%': 0, # Set to 1 by standalone.gypi in a standalone build.
@@ skipping 193 matching lines @@
         'core/fpdfdoc/ctypeset.h',
         'core/fpdfdoc/doc_action.cpp',
         'core/fpdfdoc/doc_basic.cpp',
         'core/fpdfdoc/doc_bookmark.cpp',
         'core/fpdfdoc/doc_form.cpp',
         'core/fpdfdoc/doc_formcontrol.cpp',
         'core/fpdfdoc/doc_formfield.cpp',
         'core/fpdfdoc/doc_link.cpp',
         'core/fpdfdoc/doc_metadata.cpp',
         'core/fpdfdoc/doc_ocg.cpp',
-        'core/fpdfdoc/doc_tagged.cpp',
         'core/fpdfdoc/doc_utils.cpp',
         'core/fpdfdoc/doc_utils.h',
         'core/fpdfdoc/doc_viewerPreferences.cpp',
         'core/fpdfdoc/doc_vt.cpp',
         'core/fpdfdoc/include/cpdf_aaction.h',
         'core/fpdfdoc/include/cpdf_action.h',
         'core/fpdfdoc/include/cpdf_actionfields.h',
         'core/fpdfdoc/include/cpdf_annot.h',
         'core/fpdfdoc/include/cpdf_annotlist.h',
         'core/fpdfdoc/include/cpdf_bookmark.h',
@@ skipping 13 matching lines @@
         'core/fpdfdoc/include/cpdf_occontext.h',
         'core/fpdfdoc/include/cpdf_variabletext.h',
         'core/fpdfdoc/include/cpdf_viewerpreferences.h',
         'core/fpdfdoc/include/cpvt_line.h',
         'core/fpdfdoc/include/cpvt_secprops.h',
         'core/fpdfdoc/include/cpvt_section.h',
         'core/fpdfdoc/include/cpvt_word.h',
         'core/fpdfdoc/include/cpvt_wordplace.h',
         'core/fpdfdoc/include/cpvt_wordprops.h',
         'core/fpdfdoc/include/cpvt_wordrange.h',
-        'core/fpdfdoc/include/fpdf_tagged.h',
         'core/fpdfdoc/include/ipvt_fontmap.h',
         'core/fpdfdoc/include/ipdf_formnotify.h',
         'core/fpdfdoc/pdf_vt.h',
-        'core/fpdfdoc/tagged_int.h',
       ],
     },
     {
       'target_name': 'fpdfapi',
       'type': 'static_library',
       'sources': [
         'core/fpdfapi/cpdf_modulemgr.cpp',
         'core/fpdfapi/cpdf_pagerendercontext.cpp',
         'core/fpdfapi/fpdf_cmaps/CNS1/Adobe-CNS1-UCS2_5.cpp',
         'core/fpdfapi/fpdf_cmaps/CNS1/B5pc-H_0.cpp',
@@ skipping 838 matching lines @@
             'fpdfsdk/fpdfxfa/include/fpdfxfa_app.h',
             'fpdfsdk/fpdfxfa/include/fpdfxfa_doc.h',
             'fpdfsdk/fpdfxfa/include/fpdfxfa_page.h',
             'fpdfsdk/fpdfxfa/include/fpdfxfa_util.h',
           ],
         },
       ]
     }],
   ]
 }