AEC3: Clockdrift detection

This change introduces a clockdrift detector operating on the estimated
delay of the echo path delay estimator. Each time the delay estimate
changes it is compared to previous estimates. If the estimates are
slowly increasing or decreasing, clockdrift is detected.

Four different patterns are considered clockdrift:
- k, k+1, k+2, k+3
- k, k+2, k+1, k+3
- k, k-1, k-2, k-3
- k, k-2, k-1, k-3

A delay estimate history matching the three last elements in one of the
patterns is considered probable clockdrift. Matching all four elements
is considered verified clockdrift.

If the delay is constant for some time after clockdrift is detected the
clockdrift detector will revert to no detected clockdrift.

The level of clockdrift is reported via an UMA histogram.

Bug: webrtc:10014
Change-Id: I1cce4d593e101a8b3fa99df6935e59b4243cb97a
Reviewed-on: https://webrtc-review.googlesource.com/c/111381
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Reviewed-by: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25758}

modules/audio_processing/aec3/render_delay_controller_metrics.h

@@ -14,6 +14,7 @@
 #include <stddef.h>
 
 #include "absl/types/optional.h"
+#include "modules/audio_processing/aec3/clockdrift_detector.h"
 #include "rtc_base/constructormagic.h"
 
 namespace webrtc {
@@ -26,7 +27,8 @@ class RenderDelayControllerMetrics {
   // Updates the metric with new data.
   void Update(absl::optional<size_t> delay_samples,
               size_t buffer_delay_blocks,
-              absl::optional<int> skew_shift_blocks);
+              absl::optional<int> skew_shift_blocks,
+              ClockdriftDetector::Level clockdrift);
 
   // Returns true if the metrics have just been reported, otherwise false.
   bool MetricsReported() { return metrics_reported_; }