Re-add AC3/EAC3 audio demuxing support

content/test/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/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build_overrides/v8.gni")
 import("//media/media_options.gni")
@@ skipping 328 matching lines @@
       }
     }
   }
 
   defines = [ "HAS_OUT_OF_PROC_TEST_RUNNER" ]
 
   if (proprietary_codecs && enable_hevc_demuxing) {
     defines += [ "ENABLE_HEVC_DEMUXING" ]
   }
 
+  if (proprietary_codecs && enable_ac3_eac3_demuxing) {
+    defines += [ "ENABLE_AC3_EAC3_DEMUXING" ]
+  }
+
   configs += [
     "//build/config:precompiled_headers",
     "//build/config/compiler:no_size_t_to_int_warning",
   ]
 
   deps = [
     ":browsertest_support",
     ":web_ui_test_mojo_bindings",
     "//base/allocator",
     "//base/test:test_support",
@@ skipping 539 matching lines @@
         "//media/base/android",
         "//testing/gmock",
       ]
       apk_deps = [
         "//media/base/android:media_java",
         "//ui/android:ui_java",
       ]
     }
   }
 }