tor-browser

commit c34bf72d925b11d3d39382d93e1b5fd5d76f56c3
parent f6c7777d4b7e47a702ca97235d6843b10801e76e
Author: Dan Baker <dbaker@mozilla.com>
Date:   Wed, 22 Oct 2025 13:56:27 -0600

Bug 1995393 - Vendor libwebrtc from 83740a071e

Upstream commit: https://webrtc.googlesource.com/src/+/83740a071e6951cdf7ddb6b2ea35d80083f3eb51
    Don't delete transport-cc if ccfb is disabled.

    This issue would trigger if CCFB was enabled on the sender side
    but not on the receiver side.

    Bug: webrtc:436463596
    Change-Id: Ia624d1a50934a0a4fe6273493adee8a241072fdc
    Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/403260
    Reviewed-by: Per Kjellander <perkj@webrtc.org>
    Commit-Queue: Harald Alvestrand <hta@webrtc.org>
    Cr-Commit-Position: refs/heads/main@{#45288}

Diffstat:
M
third_party/libwebrtc/README.mozilla.last-vendor
 | 
4
++--
M
third_party/libwebrtc/pc/congestion_control_integrationtest.cc
 | 
36
++++++++++++++++++++++++++++++++++++
M
third_party/libwebrtc/pc/media_session.cc
 | 
12
+++++++-----

3 files changed, 45 insertions(+), 7 deletions(-)
diff --git a/third_party/libwebrtc/README.mozilla.last-vendor b/third_party/libwebrtc/README.mozilla.last-vendor
@@ -1,4 +1,4 @@
 # ./mach python dom/media/webrtc/third_party_build/vendor-libwebrtc.py --from-local /Users/danielbaker/elm/.moz-fast-forward/moz-libwebrtc --commit mozpatches libwebrtc
-libwebrtc updated from /Users/danielbaker/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2025-10-22T19:54:03.757577+00:00.
+libwebrtc updated from /Users/danielbaker/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2025-10-22T19:56:14.992285+00:00.
 # base of lastest vendoring
-d22c6e6cb9
+83740a071e
diff --git a/third_party/libwebrtc/pc/congestion_control_integrationtest.cc b/third_party/libwebrtc/pc/congestion_control_integrationtest.cc
@@ -85,6 +85,42 @@ TEST_F(PeerConnectionCongestionControlTest, ReceiveOfferSetsCcfbFlag) {
   EXPECT_THAT(answer_str, Not(HasSubstr("transport-cc")));
 }
 
+TEST_F(PeerConnectionCongestionControlTest, SendOnlySupportDoesNotEnableCcFb) {
+  // Enable CCFB for sender, do not enable it for receiver
+  SetFieldTrials(kCallerName,
+                 "WebRTC-RFC8888CongestionControlFeedback/Enabled/");
+  SetFieldTrials(kCalleeName,
+                 "WebRTC-RFC8888CongestionControlFeedback/Disabled/");
+  ASSERT_TRUE(CreatePeerConnectionWrappers());
+  ConnectFakeSignalingForSdpOnly();
+  caller()->AddAudioVideoTracks();
+  caller()->CreateAndSetAndSignalOffer();
+  ASSERT_THAT(WaitUntil([&] { return SignalingStateStable(); }, IsTrue()),
+              IsRtcOk());
+  {
+    // Check that the callee parsed the CCFB
+    auto parsed_contents =
+        callee()->pc()->remote_description()->description()->contents();
+    EXPECT_FALSE(parsed_contents.empty());
+    for (const auto& content : parsed_contents) {
+      EXPECT_TRUE(content.media_description()->rtcp_fb_ack_ccfb());
+    }
+  }
+
+  {
+    // Check that the caller did NOT get ccfb in response
+    auto parsed_contents =
+        caller()->pc()->remote_description()->description()->contents();
+    EXPECT_FALSE(parsed_contents.empty());
+    for (const auto& content : parsed_contents) {
+      EXPECT_FALSE(content.media_description()->rtcp_fb_ack_ccfb());
+    }
+  }
+  // Check that the answer does contain transport-cc
+  std::string answer_str = absl::StrCat(*caller()->pc()->remote_description());
+  EXPECT_THAT(answer_str, HasSubstr("transport-cc"));
+}
+
 TEST_F(PeerConnectionCongestionControlTest, NegotiatingCcfbRemovesTsn) {
   SetFieldTrials("WebRTC-RFC8888CongestionControlFeedback/Enabled/");
   ASSERT_TRUE(CreatePeerConnectionWrappers());
diff --git a/third_party/libwebrtc/pc/media_session.cc b/third_party/libwebrtc/pc/media_session.cc
@@ -1341,11 +1341,13 @@ RTCError MediaSessionDescriptionFactory::AddRtpContentForAnswer(
   // RFC 8888 support. Only answer with "ack ccfb" if offer has it and
   // experiment is enabled.
   if (offer_content_description->rtcp_fb_ack_ccfb()) {
-    answer_content->set_rtcp_fb_ack_ccfb(
-        transport_desc_factory_->trials().IsEnabled(
-            "WebRTC-RFC8888CongestionControlFeedback"));
-    for (auto& codec : codecs_to_include) {
-      codec.feedback_params.Remove(FeedbackParam(kRtcpFbParamTransportCc));
+    bool use_ccfb = transport_desc_factory_->trials().IsEnabled(
+        "WebRTC-RFC8888CongestionControlFeedback");
+    if (use_ccfb) {
+      answer_content->set_rtcp_fb_ack_ccfb(use_ccfb);
+      for (auto& codec : codecs_to_include) {
+        codec.feedback_params.Remove(FeedbackParam(kRtcpFbParamTransportCc));
+      }
     }
   }
   if (!SetCodecsInAnswer(offer_content_description, codecs_to_include,