Report stats from ChannelReceive::GetAudioFrameWithInfo at 1Hz.

This is a change from the previous 100Hz frequency.
Also changing the  locks slightly in AcmReceiver so that grabbing the
neteq lock right after we've let it go, isn't necessary inside of
AcmReceiver::GetAudio and also to avoid grabbing the neteq lock while
holding the AcmReceiver lock.

Bug: webrtc:12868
Change-Id: If6ee35f3dca20eb5bdbc615123aa099ccecf57c5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/221371
Commit-Queue: Tommi <tommi@webrtc.org>
Reviewed-by: Minyue Li <minyue@webrtc.org>
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34258}

modules/audio_coding/neteq/neteq_impl.cc

@@ -258,6 +258,7 @@ void SetAudioFrameActivityAndType(bool vad_enabled,
 
 int NetEqImpl::GetAudio(AudioFrame* audio_frame,
                         bool* muted,
+                        int* current_sample_rate_hz,
                         absl::optional<Operation> action_override) {
   TRACE_EVENT0("webrtc", "NetEqImpl::GetAudio");
   MutexLock lock(&mutex_);
@@ -296,6 +297,11 @@ int NetEqImpl::GetAudio(AudioFrame* audio_frame,
     }
   }
 
+  if (current_sample_rate_hz) {
+    *current_sample_rate_hz = delayed_last_output_sample_rate_hz_.value_or(
+        last_output_sample_rate_hz_);
+  }
+
   return kOK;
 }