Replace lock with base::internal::OperationsController

BUG=901345

Change-Id: I90afa3439fedc68032ab69158d2ecfae2ba52884
Reviewed-on: https://chromium-review.googlesource.com/c/1343088
Commit-Queue: Carlos Caballero <carlscab@google.com>
Reviewed-by: Alex Clarke <alexclarke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609984}

base/task/sequence_manager/thread_controller_with_message_pump_impl.cc

@@ -4,7 +4,6 @@
 
 #include "base/task/sequence_manager/thread_controller_with_message_pump_impl.h"
 
-#include "base/auto_reset.h"
 #include "base/message_loop/message_pump.h"
 #include "base/time/tick_clock.h"
 #include "base/trace_event/trace_event.h"
@@ -46,6 +45,7 @@ ThreadControllerWithMessagePumpImpl::ThreadControllerWithMessagePumpImpl(
 }
 
 ThreadControllerWithMessagePumpImpl::~ThreadControllerWithMessagePumpImpl() {
+  operations_controller_.ShutdownAndWaitForZeroOperations();
   // Destructors of MessagePump::Delegate and ThreadTaskRunnerHandle
   // will do all the clean-up.
   // ScopedSetSequenceLocalStorageMapForCurrentThread destructor will
@@ -80,7 +80,6 @@ void ThreadControllerWithMessagePumpImpl::BindToCurrentThread(
 void ThreadControllerWithMessagePumpImpl::BindToCurrentThread(
     std::unique_ptr<MessagePump> message_pump) {
   associated_thread_->BindToCurrentThread();
-  AutoLock lock(pump_lock_);
   pump_ = std::move(message_pump);
   RunLoop::RegisterDelegateForCurrentThread(this);
   scoped_set_sequence_local_storage_map_for_current_thread_ = std::make_unique<
@@ -91,7 +90,7 @@ void ThreadControllerWithMessagePumpImpl::BindToCurrentThread(
     if (task_runner_)
       InitializeThreadTaskRunnerHandle();
   }
-  if (should_schedule_work_after_bind_)
+  if (operations_controller_.StartAcceptingOperations())
     ScheduleWork();
 }
 
@@ -113,12 +112,9 @@ void ThreadControllerWithMessagePumpImpl::WillQueueTask(
 }
 
 void ThreadControllerWithMessagePumpImpl::ScheduleWork() {
-  auto lock = AcquirePumpReadLockIfNeeded();
-
-  if (!pump_) {
-    should_schedule_work_after_bind_ = true;
+  auto operation_token = operations_controller_.TryBeginOperation();
+  if (!operation_token)
     return;
-  }
 
   // This assumes that cross thread ScheduleWork isn't frequent enough to
   // warrant ScheduleWork deduplication.
@@ -381,13 +377,6 @@ bool ThreadControllerWithMessagePumpImpl::IsTaskExecutionAllowed() const {
   return main_thread_only().task_execution_allowed;
 }
 
-Optional<MoveableAutoLock>
-ThreadControllerWithMessagePumpImpl::AcquirePumpReadLockIfNeeded() {
-  if (RunsTasksInCurrentSequence())
-    return nullopt;
-  return MoveableAutoLock(pump_lock_);
-}
-
 MessagePump* ThreadControllerWithMessagePumpImpl::GetBoundMessagePump() const {
   return pump_.get();
 }

base/task/sequence_manager/thread_controller_with_message_pump_impl.h

@@ -9,10 +9,9 @@
 
 #include "base/debug/task_annotator.h"
 #include "base/message_loop/message_pump.h"
-#include "base/optional.h"
 #include "base/run_loop.h"
+#include "base/task/common/operations_controller.h"
 #include "base/task/sequence_manager/associated_thread_id.h"
-#include "base/task/sequence_manager/moveable_auto_lock.h"
 #include "base/task/sequence_manager/sequenced_task_source.h"
 #include "base/task/sequence_manager/thread_controller.h"
 #include "base/thread_annotations.h"
@@ -140,12 +139,6 @@ class BASE_EXPORT ThreadControllerWithMessagePumpImpl
     return main_thread_only_;
   }
 
-  // Acquires a |pump_lock_| if necessary when we want to read |pump_|.
-  // Non-main thread read access should be guarded by a lock,
-  // while main-thread access can be lock-free. Write access is possible
-  // only from the main thread and needs a lock.
-  Optional<MoveableAutoLock> AcquirePumpReadLockIfNeeded();
-
   // TODO(altimin): Merge with the one in SequenceManager.
   scoped_refptr<AssociatedThreadId> associated_thread_;
   MainThreadOnly main_thread_only_;
@@ -154,12 +147,13 @@ class BASE_EXPORT ThreadControllerWithMessagePumpImpl
   scoped_refptr<SingleThreadTaskRunner> task_runner_
       GUARDED_BY(task_runner_lock_);
 
-  // Protects |pump_| and |should_schedule_work_after_bind_| as work can be
-  // scheduled from another thread before we create the pump.
-  // TODO(altimin, crbug.com/901345): Remove this lock.
-  base::Lock pump_lock_;
+  // OperationsController will only be started after |pump_| is set.
+  ::base::internal::OperationsController operations_controller_;
+
+  // Can only be set once (just before calling
+  // operations_controller_.StartAcceptingOperations()). After that only read
+  // access is allowed.
   std::unique_ptr<MessagePump> pump_;
-  bool should_schedule_work_after_bind_ = false;
 
   debug::TaskAnnotator task_annotator_;
   const TickClock* time_source_;  // Not owned.