Introduce injectable NetEqController interface.

This interface is implemented by the DecisionLogic class, which now contains the DelayManager and DelayPeakDetector.

Bug: webrtc:11005
Change-Id: I4fb69fa359e60831cf153e41f101d5b623749380
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/155176
Reviewed-by: Minyue Li <minyue@webrtc.org>
Reviewed-by: Jakob Ivarsson <jakobi@webrtc.org>
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29613}

modules/audio_coding/neteq/statistics_calculator.h

@@ -116,14 +116,6 @@ class StatisticsCalculator {
                             size_t samples_per_packet,
                             NetEqNetworkStatistics* stats);
 
-  // Populates |preferred_buffer_size_ms|, |jitter_peaks_found| and
-  // |clockdrift_ppm| in |stats|. This is a convenience method, and does not
-  // strictly have to be in the StatisticsCalculator class, but it makes sense
-  // since all other stats fields are populated by that class.
-  static void PopulateDelayManagerStats(int ms_per_packet,
-                                        const DelayManager& delay_manager,
-                                        NetEqNetworkStatistics* stats);
-
   // Returns a copy of this class's lifetime statistics. These statistics are
   // never reset.
   NetEqLifetimeStatistics GetLifetimeStatistics() const;