Bug 1822194 - Vendor libwebrtc from 36b2ad31c8

Upstream commit: https://webrtc.googlesource.com/src/+/36b2ad31c8d06c9cbc0d7ec7331b466031d010cb
    Zero extra bytes of FEC recovered packet

    rtc::CopyOnWriteBuffer::SetSize extends buffer with uninitialized memory by design.
    It is up to the user of the rtc::CopyOnWriteBuffer to ensure it is initialized.

    (cherry picked from commit f52e0152397cda785ff311394d8275f210bd5a20)

    No-Try: true
    Bug: chromium:1403397
    Change-Id: Ic0111a84bda32379770ddb1c7d24bee10d96b7a4
    Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/289041
    Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
    Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
    Cr-Original-Commit-Position: refs/heads/main@{#38959}
    Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/291540
    Reviewed-by: Per Kjellander <perkj@webrtc.org>
    Cr-Commit-Position: refs/branch-heads/5481@{#3}
    Cr-Branched-From: 2e1a9a4ae0234d4b1ea7a6fd4188afa1fb20379d-refs/heads/main@{#38901}

third_party/libwebrtc/README.moz-ff-commit

@@ -20313,3 +20313,6 @@ dc7333f9d6
 # MOZ_LIBWEBRTC_SRC=/home/bcampen/checkouts/moz-libwebrtc MOZ_LIBWEBRTC_BRANCH=mozpatches bash dom/media/webrtc/third_party_build/fast-forward-libwebrtc.sh
 # base of lastest vendoring
 e0efbd45ea
+# MOZ_LIBWEBRTC_SRC=/home/bcampen/checkouts/moz-libwebrtc MOZ_LIBWEBRTC_BRANCH=mozpatches bash dom/media/webrtc/third_party_build/fast-forward-libwebrtc.sh
+# base of lastest vendoring
+36b2ad31c8

third_party/libwebrtc/README.mozilla

@@ -13564,3 +13564,5 @@ libwebrtc updated from /home/bcampen/checkouts/moz-libwebrtc commit mozpatches o
 libwebrtc updated from /home/bcampen/checkouts/moz-libwebrtc commit mozpatches on 2023-04-02T00:35:18.174938.
 # ./mach python dom/media/webrtc/third_party_build/vendor-libwebrtc.py --from-local /home/bcampen/checkouts/moz-libwebrtc --commit mozpatches libwebrtc
 libwebrtc updated from /home/bcampen/checkouts/moz-libwebrtc commit mozpatches on 2023-04-02T00:36:36.955762.
+# ./mach python dom/media/webrtc/third_party_build/vendor-libwebrtc.py --from-local /home/bcampen/checkouts/moz-libwebrtc --commit mozpatches libwebrtc
+libwebrtc updated from /home/bcampen/checkouts/moz-libwebrtc commit mozpatches on 2023-04-02T12:16:57.189418.

third_party/libwebrtc/modules/rtp_rtcp/source/forward_error_correction.cc

@@ -573,7 +573,13 @@ bool ForwardErrorCorrection::FinishPacketRecovery(
                            "typical IP packet, and is thus dropped.";
     return false;
   }
+  size_t old_size = recovered_packet->pkt->data.size();
   recovered_packet->pkt->data.SetSize(new_size);
+  data = recovered_packet->pkt->data.MutableData();
+  if (new_size > old_size) {
+    memset(data + old_size, 0, new_size - old_size);
+  }
+
   // Set the SN field.
   ByteWriter<uint16_t>::WriteBigEndian(&data[2], recovered_packet->seq_num);
   // Set the SSRC field.