Replace RegisterExternalDecoder with decoder factory in NetEqImplTest120ms

Change-Id: I86b5f748f556be186f020a97fcc1211f953fd219

Bug: webrtc:10080
Change-Id: I86b5f748f556be186f020a97fcc1211f953fd219
Reviewed-on: https://webrtc-review.googlesource.com/c/112600
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25869}

test/function_audio_decoder_factory.h

@@ -0,0 +1,68 @@
+/*
+ *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef TEST_FUNCTION_AUDIO_DECODER_FACTORY_H_
+#define TEST_FUNCTION_AUDIO_DECODER_FACTORY_H_
+
+#include <functional>
+#include <memory>
+#include <utility>
+#include <vector>
+
+#include "absl/memory/memory.h"
+#include "api/audio_codecs/audio_decoder_factory.h"
+#include "api/audio_codecs/audio_format.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+namespace test {
+
+// A decoder factory producing decoders by calling a supplied create function.
+class FunctionAudioDecoderFactory : public AudioDecoderFactory {
+ public:
+  explicit FunctionAudioDecoderFactory(
+      std::function<std::unique_ptr<AudioDecoder>()> create)
+      : create_([create](const SdpAudioFormat&,
+                         absl::optional<AudioCodecPairId> codec_pair_id) {
+          return create();
+        }) {}
+  explicit FunctionAudioDecoderFactory(
+      std::function<std::unique_ptr<AudioDecoder>(
+          const SdpAudioFormat&,
+          absl::optional<AudioCodecPairId> codec_pair_id)> create)
+      : create_(std::move(create)) {}
+
+  // Unused by tests.
+  std::vector<AudioCodecSpec> GetSupportedDecoders() override {
+    RTC_NOTREACHED();
+    return {};
+  }
+
+  bool IsSupportedDecoder(const SdpAudioFormat& format) override {
+    return true;
+  }
+
+  std::unique_ptr<AudioDecoder> MakeAudioDecoder(
+      const SdpAudioFormat& format,
+      absl::optional<AudioCodecPairId> codec_pair_id) override {
+    return create_(format, codec_pair_id);
+  }
+
+ private:
+  const std::function<std::unique_ptr<AudioDecoder>(
+      const SdpAudioFormat&,
+      absl::optional<AudioCodecPairId> codec_pair_id)>
+      create_;
+};
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // TEST_FUNCTION_AUDIO_DECODER_FACTORY_H_