Update WebmMuxer for audio component of MediaStream recording.

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/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")
@@ skipping 199 matching lines @@
     "filters/gpu_video_decoder.cc",
     "filters/gpu_video_decoder.h",
     "filters/h264_bit_reader.cc",
     "filters/h264_bit_reader.h",
     "filters/h264_parser.cc",
     "filters/h264_parser.h",
     "filters/ivf_parser.cc",
     "filters/ivf_parser.h",
     "filters/jpeg_parser.cc",
     "filters/jpeg_parser.h",
+    "filters/opus_constants.cc",
+    "filters/opus_constants.h",
     "filters/source_buffer_range.cc",
     "filters/source_buffer_range.h",
     "filters/source_buffer_stream.cc",
     "filters/source_buffer_stream.h",
     "filters/stream_parser_factory.cc",
     "filters/stream_parser_factory.h",
     "filters/video_cadence_estimator.cc",
     "filters/video_cadence_estimator.h",
     "filters/video_renderer_algorithm.cc",
     "filters/video_renderer_algorithm.h",
@@ skipping 655 matching lines @@
       "//media/base:test_support",
       "//media/test:pipeline_integration_tests",
       "//testing/gmock",
       "//testing/gtest",
       "//third_party/ffmpeg",
       "//ui/gfx/geometry",
       "//ui/gfx:test_support",
     ]
   }
 }