firefox/libwebrtc-simplify-thread-and-lock-annotations.patch

diff --git a/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.h b/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.h
--- a/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.h
+++ b/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.h
@@ -41,22 +41,20 @@
   static void OnStreamProcess(void* data);

   void OnFormatChanged(const struct spa_pod* format);
   void ProcessBuffers();

-  rtc::RaceChecker pipewire_checker_;
-
   const rtc::scoped_refptr<PipeWireSession> session_
-      RTC_GUARDED_BY(capture_checker_);
+      RTC_GUARDED_BY(api_checker_);
+  bool initialized_ RTC_GUARDED_BY(api_checker_);
+  bool started_ RTC_GUARDED_BY(api_lock_);
   int node_id_ RTC_GUARDED_BY(capture_checker_);
   VideoCaptureCapability configured_capability_
-      RTC_GUARDED_BY(pipewire_checker_);
-  bool initialized_ RTC_GUARDED_BY(capture_checker_);
-  bool started_ RTC_GUARDED_BY(api_lock_);
+      RTC_GUARDED_BY(capture_checker_);

-  struct pw_stream* stream_ RTC_GUARDED_BY(pipewire_checker_) = nullptr;
-  struct spa_hook stream_listener_ RTC_GUARDED_BY(pipewire_checker_);
+  struct pw_stream* stream_ RTC_GUARDED_BY(capture_checker_) = nullptr;
+  struct spa_hook stream_listener_ RTC_GUARDED_BY(capture_checker_);
 };
 }  // namespace videocapturemodule
 }  // namespace webrtc

 #endif  // MODULES_VIDEO_CAPTURE_LINUX_VIDEO_CAPTURE_PIPEWIRE_H_
diff --git a/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.cc b/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.cc
--- a/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.cc
+++ b/third_party/libwebrtc/modules/video_capture/linux/video_capture_pipewire.cc
@@ -119,11 +119,10 @@
   return static_cast<spa_pod*>(spa_pod_builder_pop(builder, &frames[0]));
 }

 int32_t VideoCaptureModulePipeWire::StartCapture(
     const VideoCaptureCapability& capability) {
-  RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);
   RTC_DCHECK_RUN_ON(&api_checker_);

   if (initialized_) {
     if (capability == _requestedCapability) {
       return 0;
@@ -132,14 +131,21 @@
     }
   }

   uint8_t buffer[1024] = {};

+  // We don't want members above to be guarded by capture_checker_ as
+  // it's meant to be for members that are accessed on the API thread
+  // only when we are not capturing. The code above can be called many
+  // times while sharing instance of VideoCapturePipeWire between
+  // websites and therefore it would not follow the requirements of this
+  // checker.
+  RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);
+  PipeWireThreadLoopLock thread_loop_lock(session_->pw_main_loop_);
+
   RTC_LOG(LS_VERBOSE) << "Creating new PipeWire stream for node " << node_id_;

-  PipeWireThreadLoopLock thread_loop_lock(session_->pw_main_loop_);
-  RTC_CHECK_RUNS_SERIALIZED(&pipewire_checker_);
   pw_properties* reuse_props =
       pw_properties_new_string("pipewire.client.reuse=1");
   stream_ = pw_stream_new(session_->pw_core_, "camera-stream", reuse_props);

   if (!stream_) {
@@ -186,15 +192,17 @@

   return 0;
 }

 int32_t VideoCaptureModulePipeWire::StopCapture() {
-  RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);
   RTC_DCHECK_RUN_ON(&api_checker_);

   PipeWireThreadLoopLock thread_loop_lock(session_->pw_main_loop_);
-  RTC_CHECK_RUNS_SERIALIZED(&pipewire_checker_);
+  // PipeWireSession is guarded by API checker so just make sure we do
+  // race detection when the PipeWire loop is locked/stopped to not run
+  // any callback at this point.
+  RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);
   if (stream_) {
     pw_stream_destroy(stream_);
     stream_ = nullptr;
   }

@@ -223,18 +231,18 @@
     uint32_t id,
     const struct spa_pod* format) {
   VideoCaptureModulePipeWire* that =
       static_cast<VideoCaptureModulePipeWire*>(data);
   RTC_DCHECK(that);
-  RTC_CHECK_RUNS_SERIALIZED(&that->pipewire_checker_);
+  RTC_CHECK_RUNS_SERIALIZED(&that->capture_checker_);

   if (format && id == SPA_PARAM_Format)
     that->OnFormatChanged(format);
 }

 void VideoCaptureModulePipeWire::OnFormatChanged(const struct spa_pod* format) {
-  RTC_CHECK_RUNS_SERIALIZED(&pipewire_checker_);
+  RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);

   uint32_t media_type, media_subtype;

   if (spa_format_parse(format, &media_type, &media_subtype) < 0) {
     RTC_LOG(LS_ERROR) << "Failed to parse video format.";
@@ -329,11 +337,10 @@
     pw_stream_state state,
     const char* error_message) {
   VideoCaptureModulePipeWire* that =
       static_cast<VideoCaptureModulePipeWire*>(data);
   RTC_DCHECK(that);
-  RTC_CHECK_RUNS_SERIALIZED(&that->capture_checker_);

   MutexLock lock(&that->api_lock_);
   switch (state) {
     case PW_STREAM_STATE_STREAMING:
       that->started_ = true;
@@ -372,11 +379,11 @@
       return kVideoRotation_0;
   }
 }

 void VideoCaptureModulePipeWire::ProcessBuffers() {
-  RTC_CHECK_RUNS_SERIALIZED(&pipewire_checker_);
+  RTC_CHECK_RUNS_SERIALIZED(&capture_checker_);

   while (pw_buffer* buffer = pw_stream_dequeue_buffer(stream_)) {
     struct spa_meta_header* h;
     h = static_cast<struct spa_meta_header*>(
         spa_buffer_find_meta_data(buffer->buffer, SPA_META_Header, sizeof(*h)));
diff --git a/third_party/libwebrtc/moz-patch-stack/541f202354.no-op-cherry-pick-msg b/third_party/libwebrtc/moz-patch-stack/541f202354.no-op-cherry-pick-msg
new file mode 100644
--- /dev/null
+++ b/third_party/libwebrtc/moz-patch-stack/541f202354.no-op-cherry-pick-msg
@@ -0,0 +1 @@
+We cherry-picked this in bug 1879752.