AudioDecoderIsacT: Require caller to always specify sample rate

webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h

Index: webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h
diff --git a/webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h b/webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h
index 264cca2bf3885c67e7842ae966325c0b886ae1b5..b6b16ddb543c1011dc2e4b3eaf5492b9573e7b62 100644
--- a/webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h
+++ b/webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h
@@ -26,9 +26,6 @@ namespace webrtc {
 template <typename T>
 class AudioDecoderIsacT final : public AudioDecoder {
  public:
-  AudioDecoderIsacT();
-  explicit AudioDecoderIsacT(
-      const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo);
   explicit AudioDecoderIsacT(int sample_rate_hz);
   AudioDecoderIsacT(int sample_rate_hz,
                     const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo);
@@ -52,11 +49,8 @@ class AudioDecoderIsacT final : public AudioDecoder {
                      SpeechType* speech_type) override;
 
  private:
-  AudioDecoderIsacT(rtc::Optional<int> sample_rate_hz,
-                    const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo);
-
   typename T::instance_type* isac_state_;
-  rtc::Optional<int> sample_rate_hz_;
+  int sample_rate_hz_;
   rtc::scoped_refptr<LockedIsacBandwidthInfo> bwinfo_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioDecoderIsacT);