commit be400e465bb2410e394e26718f8efaea4f65f015
author Markus Handell <handellm@webrtc.org> Tue Nov 08 11:14:23 2022
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Tue Nov 08 12:23:40 2022
tree 1608cc7af1ec2516a6e70f633d1cf981856607eb
parent 822794d491ad3fde135a2cb4cb8b540e944828af

Metronome: disable & refactor for single-threaded operation.

The Chromium implementation unfortunately has a rare deadlock.
Rather than patching that up, we're changing the metronome
implementation to be able to use a single-threaded environment
instead.

The metronome functionality is disabled in VideoReceiveStream2
construction inside call.cc.

The new design does not have listener registration or
deresigstration and instead accepts and invokes callbacks, on
the same sequence that requested the callback. This allows
the clients to use features such as WeakPtrFactories or
ScopedThreadSafety for cancellation.

The CL will be followed up with cleanup CLs that removes
registration APIs once downstream consumers have adapted.

Bug: chromium:1381982
Change-Id: I43732d1971e2276c39b431a04365cd2fc3c55c25
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/282280
Reviewed-by: Per Kjellander <perkj@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Evan Shrubsole <eshr@webrtc.org>
Commit-Queue: Markus Handell <handellm@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38582}

pc/test/integration_test_helpers.h

diff --git a/pc/test/integration_test_helpers.h b/pc/test/integration_test_helpers.h
index 1a1172c..21ddacb 100644
--- a/pc/test/integration_test_helpers.h
+++ b/pc/test/integration_test_helpers.h
@@ -180,20 +180,15 @@
 
 class TaskQueueMetronome : public webrtc::Metronome {
  public:
-  TaskQueueMetronome(TaskQueueFactory* factory, TimeDelta tick_period);
-  ~TaskQueueMetronome() override;
+  explicit TaskQueueMetronome(TimeDelta tick_period);
 
   // webrtc::Metronome implementation.
-  void AddListener(TickListener* listener) override;
-  void RemoveListener(TickListener* listener) override;
+  void RequestCallOnNextTick(absl::AnyInvocable<void() &&> callback) override;
   TimeDelta TickPeriod() const override;
 
  private:
-  Mutex mutex_;
   const TimeDelta tick_period_;
-  std::set<TickListener*> listeners_ RTC_GUARDED_BY(mutex_);
-  RepeatingTaskHandle tick_task_;
-  rtc::TaskQueue queue_;
+  std::vector<absl::AnyInvocable<void() &&>> callbacks_;
 };
 
 class SignalingMessageReceiver {
@@ -775,8 +770,8 @@
     pc_factory_dependencies.task_queue_factory =
         webrtc::CreateDefaultTaskQueueFactory();
     pc_factory_dependencies.trials = std::make_unique<FieldTrialBasedConfig>();
-    pc_factory_dependencies.metronome = std::make_unique<TaskQueueMetronome>(
-        pc_factory_dependencies.task_queue_factory.get(), TimeDelta::Millis(8));
+    pc_factory_dependencies.metronome =
+        std::make_unique<TaskQueueMetronome>(TimeDelta::Millis(8));
     cricket::MediaEngineDependencies media_deps;
     media_deps.task_queue_factory =
         pc_factory_dependencies.task_queue_factory.get();