Revert of Opus implementation of the AudioDecoderFactoryTemplate API

webrtc/test/fuzzers/audio_decoder_opus_redundant_fuzzer.cc

Index: webrtc/test/fuzzers/audio_decoder_opus_redundant_fuzzer.cc
diff --git a/webrtc/test/fuzzers/audio_decoder_opus_redundant_fuzzer.cc b/webrtc/test/fuzzers/audio_decoder_opus_redundant_fuzzer.cc
index e623301a7a41c8ee18367c45190a1ce1f61f8f1a..48b8b25da33ddfe401977809b8a30da2f391fa7b 100644
--- a/webrtc/test/fuzzers/audio_decoder_opus_redundant_fuzzer.cc
+++ b/webrtc/test/fuzzers/audio_decoder_opus_redundant_fuzzer.cc
@@ -14,7 +14,7 @@
 namespace webrtc {
 void FuzzOneInput(const uint8_t* data, size_t size) {
   const size_t channels = (size % 2) + 1;  // 1 or 2 channels.
-  AudioDecoderOpusImpl dec(channels);
+  AudioDecoderOpus dec(channels);
   const int kSampleRateHz = 48000;
   const size_t kAllocatedOuputSizeSamples = kSampleRateHz / 10;  // 100 ms.
   int16_t output[kAllocatedOuputSizeSamples];