Delete unimplemented methods from the NetEq interface.

Bug: None
Change-Id: I51949a096c445813acc6649676e32c575732ef40
Reviewed-on: https://webrtc-review.googlesource.com/95643
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24469}

modules/audio_coding/neteq/include/neteq.h

@@ -96,7 +96,7 @@ class NetEq {
     bool for_test_no_time_stretching = false;  // Use only for testing.
   };
 
-  enum ReturnCodes { kOK = 0, kFail = -1, kNotImplemented = -2 };
+  enum ReturnCodes { kOK = 0, kFail = -1 };
 
   // Creates a new NetEq object, with parameters set in |config|. The |config|
   // object will only have to be valid for the duration of the call to this
@@ -180,9 +180,6 @@ class NetEq {
   // the |max_delay_ms| value in the NetEq::Config struct.
   virtual bool SetMaximumDelay(int delay_ms) = 0;
 
-  // Not implemented.
-  virtual int SetTargetDelay() = 0;
-
   // Returns the current target delay in ms. This includes any extra delay
   // requested through SetMinimumDelay.
   virtual int TargetDelayMs() const = 0;
@@ -235,12 +232,6 @@ class NetEq {
   virtual absl::optional<SdpAudioFormat> GetDecoderFormat(
       int payload_type) const = 0;
 
-  // Not implemented.
-  virtual int SetTargetNumberOfChannels() = 0;
-
-  // Not implemented.
-  virtual int SetTargetSampleRate() = 0;
-
   // Flushes both the packet buffer and the sync buffer.
   virtual void FlushBuffers() = 0;