Re-add AC3/EAC3 audio demuxing support

media/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/buildflag_header.gni")
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/features.gni")
 import("//build/config/linux/pkg_config.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
 import("//testing/test.gni")
 
 buildflag_header("media_features") {
   header = "media_features.h"
 
-  flags =
-      [ "ENABLE_MSE_MPEG2TS_STREAM_PARSER=$enable_mse_mpeg2ts_stream_parser" ]
+  flags = [
+    "ENABLE_AC3_EAC3_AUDIO_DEMUXING=$enable_ac3_eac3_audio_demuxing",
+    "ENABLE_MSE_MPEG2TS_STREAM_PARSER=$enable_mse_mpeg2ts_stream_parser",
+  ]
 }
 
 # Common configuration for targets in the media directory.
 # NOT for exporting.
 config("media_config") {
   defines = []
   if (!media_use_libvpx) {
     defines += [ "MEDIA_DISABLE_LIBVPX" ]
   }
   if (!media_use_ffmpeg) {
@@ skipping 897 matching lines @@
       "//media/base:test_support",
       "//media/test:pipeline_integration_tests",
       "//testing/gmock",
       "//testing/gtest",
       "//third_party/ffmpeg",
       "//ui/gfx:test_support",
       "//ui/gfx/geometry",
     ]
   }
 }