Revert removal of AudioBufferCallback

third_party/WebKit/Source/modules/webaudio/BUILD.gn

 # Copyright 2016 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("//third_party/WebKit/Source/modules/modules.gni")
 
 blink_modules_sources("webaudio") {
   sources = [
     "AnalyserNode.cpp",
     "AnalyserNode.h",
     "AsyncAudioDecoder.cpp",
     "AsyncAudioDecoder.h",
     "AudioBasicInspectorNode.cpp",
     "AudioBasicInspectorNode.h",
     "AudioBasicProcessorHandler.cpp",
     "AudioBasicProcessorHandler.h",
     "AudioBuffer.cpp",
     "AudioBuffer.h",
+    "AudioBufferCallback.h",
     "AudioBufferSourceNode.cpp",
     "AudioBufferSourceNode.h",
     "AudioContext.cpp",
     "AudioContext.h",
     "AudioDestinationNode.cpp",
     "AudioDestinationNode.h",
     "AudioListener.cpp",
     "AudioListener.h",
     "AudioNode.cpp",
     "AudioNode.h",
@@ skipping 91 matching lines @@
     "WaveShaperProcessor.h",
     "WindowAudioWorklet.cpp",
     "WindowAudioWorklet.h",
   ]
 
   if (is_win) {
     # Result of 32-bit shift implicitly converted to 64 bits.
     cflags = [ "/wd4334" ]
   }
 }