Make an enum class out of NetEqDecoder, and hide the neteq_decoders_ table

webrtc/modules/audio_coding/neteq/tools/neteq_quality_test.h

 /*
  *  Copyright (c) 2014 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.
  */
 
@@ skipping 48 matching lines @@
   double prob_trans_01_;
   bool lost_last_;
   rtc::scoped_ptr<UniformLoss> uniform_loss_model_;
 };
 
 class NetEqQualityTest : public ::testing::Test {
  protected:
   NetEqQualityTest(int block_duration_ms,
                    int in_sampling_khz,
                    int out_sampling_khz,
-                   enum NetEqDecoder decoder_type);
+                   NetEqDecoder decoder_type);
   virtual ~NetEqQualityTest();
 
   void SetUp() override;
 
   // EncodeBlock(...) does the following:
   // 1. encodes a block of audio, saved in |in_data| and has a length of
   // |block_size_samples| (samples per channel),
   // 2. save the bit stream to |payload| of |max_bytes| bytes in size,
   // 3. returns the length of the payload (in bytes),
   virtual int EncodeBlock(int16_t* in_data, size_t block_size_samples,
@@ skipping 11 matching lines @@
   // Transmit() uses |rtp_generator_| to generate a packet and passes it to
   // |neteq_|.
   int Transmit();
 
   // Runs encoding / transmitting / decoding.
   void Simulate();
 
   // Write to log file. Usage Log() << ...
   std::ofstream& Log();
 
-  enum NetEqDecoder decoder_type_;
+  NetEqDecoder decoder_type_;
   const int channels_;
 
  private:
   int decoded_time_ms_;
   int decodable_time_ms_;
   double drift_factor_;
   int packet_loss_rate_;
   const int block_duration_ms_;
   const int in_sampling_khz_;
   const int out_sampling_khz_;
@@ skipping 20 matching lines @@
   rtc::scoped_ptr<int16_t[]> out_data_;
   WebRtcRTPHeader rtp_header_;
 
   size_t total_payload_size_bytes_;
 };
 
 }  // namespace test
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_TOOLS_NETEQ_QUALITY_TEST_H_