Revert 290359 "Remove AudioBuffersState class."

trunk/src/media/audio/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("//media/media_options.gni")
 
 # When libpulse is not directly linked, use stubs to allow for dlopening of the
 # binary.
 if (!linux_link_pulseaudio) {
   action("pulse_generate_stubs") {
@@ skipping 18 matching lines @@
       "-p", "media/audio/pulse",
     ]
 
     args += rebase_path(sources, root_build_dir)
   }
 }
 
 source_set("audio") {
   sources = [
     "agc_audio_stream.h",
+    "audio_buffers_state.cc",
+    "audio_buffers_state.h",
     "audio_device_name.cc",
     "audio_device_name.h",
     "audio_device_thread.cc",
     "audio_device_thread.h",
     "audio_input_controller.cc",
     "audio_input_controller.h",
     "audio_input_device.cc",
     "audio_input_device.h",
     "audio_input_ipc.cc",
     "audio_input_ipc.h",
@@ skipping 271 matching lines @@
       "win/core_audio_util_win_unittest.cc",
     ]
   }
 
   if (use_alsa) {
     sources += [
       "alsa/alsa_output_unittest.cc",
     ]
   }
 }