commit af1b9ceb62dce3462083f9a44e26ee6d79639cef
author Artem Titov <titovartem@webrtc.org> Thu May 14 13:52:14 2020
committer Commit Bot <commit-bot@chromium.org> Thu May 14 13:52:53 2020
tree 0199633c7991def19ce9217b8b8e0933f09f9a58
parent 87a6e5ab4d8f0baf4e2a9b7752b43d825f9c0ce1

Revert "Revert back to using the task_queue_ for guarding access."

This reverts commit 475006d4a30f8bc47f82eb540a6a066da2829095.

Reason for revert: Speculative revert. Breaks downstream project

Original change's description:
> Revert back to using the task_queue_ for guarding access.
> 
> This removes the SequenceChecker that was temporarily used while
> the rtc::Thread TQ implementation was being fixed.
> 
> Bug: none
> Change-Id: Iaa46e47371211ac0a97b2dcaf23cef12b43ee8ea
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/175081
> Commit-Queue: Tommi <tommi@webrtc.org>
> Reviewed-by: Sebastian Jansson <srte@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#31256}

TBR=tommi@webrtc.org,srte@webrtc.org

Change-Id: I17a12bdca888a63f2fd161da30c0def5b9c3d04e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: none
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/175103
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31258}

rtc_base/task_utils/repeating_task.cc

diff --git a/rtc_base/task_utils/repeating_task.cc b/rtc_base/task_utils/repeating_task.cc
index 3b84701..71911e6 100644
--- a/rtc_base/task_utils/repeating_task.cc
+++ b/rtc_base/task_utils/repeating_task.cc
@@ -21,12 +21,13 @@
                                      TimeDelta first_delay)
     : task_queue_(task_queue),
       next_run_time_(Timestamp::Micros(rtc::TimeMicros()) + first_delay) {
+  sequence_checker_.Detach();
 }
 
 RepeatingTaskBase::~RepeatingTaskBase() = default;
 
 bool RepeatingTaskBase::Run() {
-  RTC_DCHECK_RUN_ON(task_queue_);
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   // Return true to tell the TaskQueue to destruct this object.
   if (next_run_time_.IsPlusInfinity())
     return true;
@@ -52,7 +53,7 @@
 }
 
 void RepeatingTaskBase::Stop() {
-  RTC_DCHECK_RUN_ON(task_queue_);
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
   RTC_DCHECK(next_run_time_.IsFinite());
   next_run_time_ = Timestamp::PlusInfinity();
 }

rtc_base/task_utils/repeating_task.h

diff --git a/rtc_base/task_utils/repeating_task.h b/rtc_base/task_utils/repeating_task.h
index f7ae55e..75d03bf 100644
--- a/rtc_base/task_utils/repeating_task.h
+++ b/rtc_base/task_utils/repeating_task.h
@@ -19,6 +19,7 @@
 #include "api/task_queue/task_queue_base.h"
 #include "api/units/time_delta.h"
 #include "api/units/timestamp.h"
+#include "rtc_base/synchronization/sequence_checker.h"
 
 namespace webrtc {
 
@@ -40,7 +41,14 @@
   TaskQueueBase* const task_queue_;
   // This is always finite, except for the special case where it's PlusInfinity
   // to signal that the task should stop.
-  Timestamp next_run_time_ RTC_GUARDED_BY(task_queue_);
+  Timestamp next_run_time_ RTC_GUARDED_BY(sequence_checker_);
+  // We use a SequenceChecker to check for correct usage instead of using
+  // RTC_DCHECK_RUN_ON(task_queue_). This is to work around a compatibility
+  // issue with some TQ implementations such as rtc::Thread that don't
+  // consistently set themselves as the 'current' TQ when running tasks.
+  // The SequenceChecker detects those implementations differently but gives
+  // the same effect as far as thread safety goes.
+  SequenceChecker sequence_checker_;
 };
 
 // The template closure pattern is based on rtc::ClosureTask.