Introduce AudioDiscardHelper. Refactor audio decoders to use it.

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 201 matching lines @@
         'base/audio_buffer_queue.h',
         'base/audio_capturer_source.h',
         'base/audio_buffer_converter.cc',
         'base/audio_buffer_converter.h',
         'base/audio_converter.cc',
         'base/audio_converter.h',
         'base/audio_decoder.cc',
         'base/audio_decoder.h',
         'base/audio_decoder_config.cc',
         'base/audio_decoder_config.h',
+        'base/audio_discard_helper.cc',
+        'base/audio_discard_helper.h',
         'base/audio_fifo.cc',
         'base/audio_fifo.h',
         'base/audio_hardware_config.cc',
         'base/audio_hardware_config.h',
         'base/audio_hash.cc',
         'base/audio_hash.h',
         'base/audio_pull_fifo.cc',
         'base/audio_pull_fifo.h',
         'base/audio_renderer.cc',
         'base/audio_renderer.h',
@@ skipping 731 matching lines @@
         'audio/win/audio_output_win_unittest.cc',
         'audio/win/core_audio_util_win_unittest.cc',
         'base/android/media_codec_bridge_unittest.cc',
         'base/android/media_drm_bridge_unittest.cc',
         'base/android/media_source_player_unittest.cc',
         'base/audio_buffer_converter_unittest.cc',
         'base/audio_buffer_unittest.cc',
         'base/audio_buffer_queue_unittest.cc',
         'base/audio_bus_unittest.cc',
         'base/audio_converter_unittest.cc',
+        'base/audio_discard_helper_unittest.cc',
         'base/audio_fifo_unittest.cc',
         'base/audio_hardware_config_unittest.cc',
         'base/audio_hash_unittest.cc',
         'base/audio_pull_fifo_unittest.cc',
         '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',
@@ skipping 706 matching lines @@
                   ],
                 }],
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }