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

webrtc/modules/audio_coding/neteq/tools/neteq_performance_test.cc

Index: webrtc/modules/audio_coding/neteq/tools/neteq_performance_test.cc
diff --git a/webrtc/modules/audio_coding/neteq/tools/neteq_performance_test.cc b/webrtc/modules/audio_coding/neteq/tools/neteq_performance_test.cc
index 57397e14a3812ed6b5522b7d5b569134097a677e..42bfc1c8f1a55c2c78c90798981f64bc4449e9f4 100644
--- a/webrtc/modules/audio_coding/neteq/tools/neteq_performance_test.cc
+++ b/webrtc/modules/audio_coding/neteq/tools/neteq_performance_test.cc
@@ -32,7 +32,8 @@ int64_t NetEqPerformanceTest::Run(int runtime_ms,
   const std::string kInputFileName =
       webrtc::test::ResourcePath("audio_coding/testfile32kHz", "pcm");
   const int kSampRateHz = 32000;
-  const webrtc::NetEqDecoder kDecoderType = webrtc::kDecoderPCM16Bswb32kHz;
+  const webrtc::NetEqDecoder kDecoderType =
+      webrtc::NetEqDecoder::kDecoderPCM16Bswb32kHz;
   const int kPayloadType = 95;
 
   // Initialize NetEq instance.