Bug 1909234 - Vendor libwebrtc from 876d0c9881

Upstream commit: https://webrtc.googlesource.com/src/+/876d0c9881eab8e7f8389812eb3738bdd374aa22
    Fix use-of-uninitialized-value in NetEq tests.

    The new version of MSan (rolled by [1]) detects the following:

    ```
    ==39908==WARNING: MemorySanitizer: use-of-uninitialized-value
        #0 0x5591400a52ef in GetPlayoutDelayMs ./../../modules/audio_coding/neteq/decision_logic.cc:466:35
        #1 0x5591400a52ef in webrtc::DecisionLogic::ExpectedPacketAvailable(webrtc::NetEqController::NetEqStatus) ./../../modules/audio_coding/neteq/decision_logic.cc:311:36
        #2 0x5591400a39e9 in webrtc::DecisionLogic::GetDecision(webrtc::NetEqController::NetEqStatus const&, bool*) ./../../modules/audio_coding/neteq/decision_logic.cc:0:0
        #3 0x55913cf590c9 in webrtc::DecisionLogicTest_PreemptiveExpand_Test::TestBody() ./../../modules/audio_coding/neteq/decision_logic_unittest.cc:139:3
        #4 0x55913ef28283 in HandleExceptionsInMethodIfSupported<testing::Test, void> ./../../third_party/googletest/src/googletest/src/gtest.cc:0:3
        #5 0x55913ef28283 in testing::Test::Run() ./../../third_party/googletest/src/googletest/src/gtest.cc:2710:5
        #6 0x55913ef2ab46 in testing::TestInfo::Run() ./../../third_party/googletest/src/googletest/src/gtest.cc:2856:11
        #7 0x55913ef2da34 in testing::TestSuite::Run() ./../../third_party/googletest/src/googletest/src/gtest.cc:3034:30
        #8 0x55913ef621e8 in testing::internal::UnitTestImpl::RunAllTests() ./../../third_party/googletest/src/googletest/src/gtest.cc:5964:44
        #9 0x55913ef60f54 in HandleExceptionsInMethodIfSupported<testing::internal::UnitTestImpl, bool> ./../../third_party/googletest/src/googletest/src/gtest.cc:0:0
        #10 0x55913ef60f54 in testing::UnitTest::Run() ./../../third_party/googletest/src/googletest/src/gtest.cc:5543:10
        #11 0x55913ee1a944 in RUN_ALL_TESTS ./../../third_party/googletest/src/googletest/include/gtest/gtest.h:2334:73
        #12 0x55913ee1a944 in webrtc::(anonymous namespace)::TestMainImpl::Run(int, char**) ./../../test/test_main_lib.cc:203:21
        #13 0x55913cbd36b8 in main ./../../test/test_main.cc:72:16
        #14 0x7fdb18c73082 in __libc_start_main /build/glibc-LcI20x/glibc-2.31/csu/../csu/libc-start.c:308:16
        #15 0x55913cb3e1a9 in _start ??:0:0
    ```

    [1] - https://webrtc-review.googlesource.com/c/src/+/353620

    Bug: b/344970813
    Change-Id: I9b5d7791e68b4c494168ba9f007a3099ae21fed4
    Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/353581
    Auto-Submit: Mirko Bonadei <mbonadei@webrtc.org>
    Reviewed-by: Jakob Ivarsson‎ <jakobi@webrtc.org>
    Commit-Queue: Jakob Ivarsson‎ <jakobi@webrtc.org>
    Cr-Commit-Position: refs/heads/main@{#42433}

third_party/libwebrtc/README.moz-ff-commit

@@ -31071,3 +31071,6 @@ fe34363ca0
 # MOZ_LIBWEBRTC_SRC=/home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc MOZ_LIBWEBRTC_BRANCH=mozpatches bash dom/media/webrtc/third_party_build/fast-forward-libwebrtc.sh
 # base of lastest vendoring
 06e88bbb5a
+# MOZ_LIBWEBRTC_SRC=/home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc MOZ_LIBWEBRTC_BRANCH=mozpatches bash dom/media/webrtc/third_party_build/fast-forward-libwebrtc.sh
+# base of lastest vendoring
+876d0c9881

third_party/libwebrtc/README.mozilla

@@ -20738,3 +20738,5 @@ libwebrtc updated from /home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebr
 libwebrtc updated from /home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2024-07-29T17:09:35.313970.
 # ./mach python dom/media/webrtc/third_party_build/vendor-libwebrtc.py --from-local /home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc --commit mozpatches libwebrtc
 libwebrtc updated from /home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2024-07-29T17:10:40.675068.
+# ./mach python dom/media/webrtc/third_party_build/vendor-libwebrtc.py --from-local /home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc --commit mozpatches libwebrtc
+libwebrtc updated from /home/bcampen/checkouts/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2024-07-29T17:11:54.967066.

third_party/libwebrtc/modules/audio_coding/neteq/decision_logic_unittest.cc

@@ -43,6 +43,7 @@ NetEqController::NetEqStatus CreateNetEqStatus(NetEq::Mode last_mode,
       current_delay_ms * kSamplesPerMs;
   status.packet_buffer_info.dtx_or_cng = false;
   status.next_packet = {status.target_timestamp, false, false};
+  status.sync_buffer_samples = 0;
   return status;
 }