Let NetEq use the PLC output from a decoder

This change enables NetEq to use the packet concealment audio (aka
PLC) produced by a decoder. The change also includes a new API to the
AudioDecoder interface, which lets the decoder implementation generate
and deliver concealment audio.

Bug: webrtc:9180
Change-Id: Icaacebccf645d4694b0d2d6310f6f2c7132881c4
Reviewed-on: https://webrtc-review.googlesource.com/96340
Commit-Queue: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Minyue Li <minyue@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24738}
diff --git a/modules/audio_coding/neteq/normal.cc b/modules/audio_coding/neteq/normal.cc
index 83f7616..713bfb6 100644
--- a/modules/audio_coding/neteq/normal.cc
+++ b/modules/audio_coding/neteq/normal.cc
@@ -41,7 +41,7 @@
     output->Clear();
     return 0;
   }
-  output->PushBackInterleaved(input, length);
+  output->PushBackInterleaved(rtc::ArrayView<const int16_t>(input, length));
 
   const int fs_mult = fs_hz_ / 8000;
   RTC_DCHECK_GT(fs_mult, 0);