Re-add AC3/EAC3 audio demuxing support

media/media.gyp

 # Copyright (c) 2012 The Chromium 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,
     # Override to dynamically link the cras (ChromeOS audio) library.
     'use_cras%': 0,
     # Option e.g. for Linux distributions to link pulseaudio directly
@@ skipping 15 matching lines @@
       }, {
         'use_alsa%': 0,
         'use_pulseaudio%': 0,
       }],
       # low memory buffer is used in non-Android based chromecast build due to hardware limitation.
       ['chromecast==1 and OS!="android"', {
         'use_low_memory_buffer%': 1,
       }, {
         'use_low_memory_buffer%': 0,
       }],
-      ['chromecast == 1', {
+      ['proprietary_codecs==1 and chromecast==1', {
+        # Enable AC3/EAC3 audio demuxing. Actual decoding must be provided by
+        # the platform (or HDMI sink in Chromecast for audio pass-through case).
+        'enable_ac3_eac3_audio_demuxing%': 1,
         'enable_mse_mpeg2ts_stream_parser%': 1,
       }, {
+        'enable_ac3_eac3_audio_demuxing%': 0,
         'enable_mse_mpeg2ts_stream_parser%': 0,
       }],
       ['chromecast==1', {
         # Enable HEVC/H265 demuxing. Actual decoding must be provided by the
         # platform.
         'enable_hevc_demuxing%': 1,
       }, {
         'enable_hevc_demuxing%': 0,
       }],
     ],
   },
   'includes': [
     'media_cdm.gypi',
     'media_variables.gypi',
   ],
   'targets': [
     {
       # GN version: //media:media_features
       'target_name': 'media_features',
       'includes': [ '../build/buildflag_header.gypi' ],
       'variables': {
         'buildflag_header_path': 'media/media_features.h',
         'buildflag_flags': [
+          "ENABLE_AC3_EAC3_AUDIO_DEMUXING=<(enable_ac3_eac3_audio_demuxing)",
           "ENABLE_MSE_MPEG2TS_STREAM_PARSER=<(enable_mse_mpeg2ts_stream_parser)",
         ],
       },
     },
     {
       # GN version: //media
       'target_name': 'media',
       'type': '<(component)',
       'dependencies': [
         'media_features',
@@ skipping 2091 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }