Replace WebAudio MediaCodec usage with FFmpeg. A ~4x improvement.

media/base/android/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/android/rules.gni")
 import("//build/config/arm.gni")
 import("//build/config/ui.gni")
 import("//media/media_options.gni")
 
@@ skipping 46 matching lines @@
     "media_statistics.cc",
     "media_statistics.h",
     "media_task_runner.cc",
     "media_task_runner.h",
     "media_url_interceptor.h",
     "provision_fetcher.h",
     "sdk_media_codec_bridge.cc",
     "sdk_media_codec_bridge.h",
     "video_decoder_job.cc",
     "video_decoder_job.h",
-    "webaudio_media_codec_bridge.cc",
-    "webaudio_media_codec_bridge.h",
-    "webaudio_media_codec_info.h",
   ]
   configs += [
     "//media:media_config",
     "//media:media_implementation",
   ]
   deps = [
     ":media_jni_headers",
     "//media:shared_memory_support",
     "//third_party/widevine/cdm:version_h",
     "//ui/gl",
@@ skipping 27 matching lines @@
 
 generate_jni("media_jni_headers") {
   sources = [
     "java/src/org/chromium/media/AudioManagerAndroid.java",
     "java/src/org/chromium/media/AudioRecordInput.java",
     "java/src/org/chromium/media/MediaCodecBridge.java",
     "java/src/org/chromium/media/MediaCodecUtil.java",
     "java/src/org/chromium/media/MediaDrmBridge.java",
     "java/src/org/chromium/media/MediaPlayerBridge.java",
     "java/src/org/chromium/media/MediaPlayerListener.java",
-    "java/src/org/chromium/media/WebAudioMediaCodecBridge.java",
   ]
   jni_package = "media"
 }
 
 generate_jni("video_capture_jni_headers") {
   sources = [
     "java/src/org/chromium/media/VideoCapture.java",
     "java/src/org/chromium/media/VideoCaptureFactory.java",
   ]
   jni_package = "media"
 }
 
 java_cpp_enum("media_java_enums_srcjar") {
   sources = [
     "//media/capture/video/android/video_capture_device_android.h",
     "//media/capture/video/video_capture_device.h",
   ]
 }
 
 android_library("media_java") {
   deps = [
     "//base:base_java",
   ]
 
   srcjar_deps = [ ":media_java_enums_srcjar" ]
 
   DEPRECATED_java_in_dir = "java/src"
 }