Expose the internal MatrixBuilder class as ChannelMixingMatrix.

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 243 matching lines @@
         'base/byte_queue.cc',
         'base/byte_queue.h',
         'base/cdm_callback_promise.cc',
         'base/cdm_callback_promise.h',
         'base/cdm_factory.cc',
         'base/cdm_factory.h',
         'base/cdm_promise.cc',
         'base/cdm_promise.h',
         'base/channel_mixer.cc',
         'base/channel_mixer.h',
+        'base/channel_mixing_matrix.cc',
+        'base/channel_mixing_matrix.h',
         'base/container_names.cc',
         'base/container_names.h',
         'base/data_buffer.cc',
         'base/data_buffer.h',
         'base/data_source.cc',
         'base/data_source.h',
         'base/decoder_buffer.cc',
         'base/decoder_buffer.h',
         'base/decoder_buffer_queue.cc',
         'base/decoder_buffer_queue.h',
@@ skipping 932 matching lines @@
         'base/audio_renderer_mixer_input_unittest.cc',
         'base/audio_renderer_mixer_unittest.cc',
         'base/audio_splicer_unittest.cc',
         'base/audio_timestamp_helper_unittest.cc',
         'base/audio_video_metadata_extractor_unittest.cc',
         'base/bind_to_current_loop_unittest.cc',
         'base/bit_reader_unittest.cc',
         'base/callback_holder.h',
         'base/callback_holder_unittest.cc',
         'base/channel_mixer_unittest.cc',
+        'base/channel_mixing_matrix_unittest.cc',
         'base/container_names_unittest.cc',
         'base/data_buffer_unittest.cc',
         'base/decoder_buffer_queue_unittest.cc',
         'base/decoder_buffer_unittest.cc',
         'base/djb2_unittest.cc',
         'base/gmock_callback_support_unittest.cc',
         'base/media_file_checker_unittest.cc',
         'base/multi_channel_resampler_unittest.cc',
         'base/pipeline_unittest.cc',
         'base/ranges_unittest.cc',
@@ skipping 736 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'media_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }