[base] Rename SequencedTaskSource::OnSystemIdle() to OnIdle().

Reason: The method is invoked when the thread running the task source
is idle, not when the system idle.

Bug: 1503967
Change-Id: I9f59259056ee834b3789a6aeb4fcb37808aeb7c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5131495
Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Commit-Queue: Francois Pierre Doray <fdoray@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1239116}

base/task/sequence_manager/sequence_manager_impl.cc

@@ -763,7 +763,7 @@ bool SequenceManagerImpl::HasPendingHighResolutionTasks() {
   return main_thread_only().wake_up_queue->has_pending_high_resolution_tasks();
 }
 
-bool SequenceManagerImpl::OnSystemIdle() {
+bool SequenceManagerImpl::OnIdle() {
   bool have_work_to_do = false;
   if (main_thread_only().time_domain) {
     auto wakeup = main_thread_only().wake_up_queue->GetNextDelayedWakeUp();

base/task/sequence_manager/sequence_manager_impl.h

@@ -141,7 +141,7 @@ class BASE_EXPORT SequenceManagerImpl
       LazyNow* lazy_now,
       SelectTaskOption option = SelectTaskOption::kDefault) override;
   bool HasPendingHighResolutionTasks() override;
-  bool OnSystemIdle() override;
+  bool OnIdle() override;
   void MaybeEmitTaskDetails(
       perfetto::EventContext& ctx,
       const SequencedTaskSource::SelectedTask& selected_task) const override;
@@ -342,8 +342,8 @@ class BASE_EXPORT SequenceManagerImpl
     ObserverList<CurrentThread::DestructionObserver>::Unchecked
         destruction_observers;
 
-    // If non-null, invoked the next time OnSystemIdle() completes without
-    // scheduling additional work.
+    // If non-null, invoked the next time OnIdle() completes without scheduling
+    // additional work.
     OnceClosure on_next_idle_callback;
   };
 

base/task/sequence_manager/sequence_manager_impl_unittest.cc

@@ -4771,20 +4771,20 @@ class MockTimeDomain : public TimeDomain {
 
 }  // namespace
 
-TEST_P(SequenceManagerTest, OnSystemIdleTimeDomainNotification) {
+TEST_P(SequenceManagerTest, OnIdleTimeDomainNotification) {
   if (GetUnderlyingRunnerType() != RunnerType::kMessagePump)
     return;
 
   auto queue = CreateTaskQueue();
 
-  // If we call OnSystemIdle, we expect registered TimeDomains to receive a call
-  // to MaybeFastForwardToWakeUp.  If no run loop has requested quit on idle,
-  // the parameter passed in should be false.
+  // If we call OnIdle, we expect registered TimeDomains to receive a call to
+  // MaybeFastForwardToWakeUp.  If no run loop has requested quit on idle, the
+  // parameter passed in should be false.
   StrictMock<MockTimeDomain> mock_time_domain;
   sequence_manager()->SetTimeDomain(&mock_time_domain);
   EXPECT_CALL(mock_time_domain, MaybeFastForwardToWakeUp(false))
       .WillOnce(Return(false));
-  sequence_manager()->OnSystemIdle();
+  sequence_manager()->OnIdle();
   sequence_manager()->ResetTimeDomain();
   Mock::VerifyAndClearExpectations(&mock_time_domain);
 
@@ -4795,7 +4795,7 @@ TEST_P(SequenceManagerTest, OnSystemIdleTimeDomainNotification) {
         EXPECT_CALL(mock_time_domain, MaybeFastForwardToWakeUp(true))
             .WillOnce(Return(false));
         sequence_manager()->SetTimeDomain(&mock_time_domain);
-        sequence_manager()->OnSystemIdle();
+        sequence_manager()->OnIdle();
         sequence_manager()->ResetTimeDomain();
       }));
 

base/task/sequence_manager/sequenced_task_source.h

@@ -78,7 +78,7 @@ class SequencedTaskSource {
   // Called when we have run out of immediate work.  If more immediate work
   // becomes available as a result of any processing done by this callback,
   // return true to schedule a future DoWork.
-  virtual bool OnSystemIdle() = 0;
+  virtual bool OnIdle() = 0;
 
   // Called prior to running `selected_task` to emit trace event data for it.
   virtual void MaybeEmitTaskDetails(

base/task/sequence_manager/thread_controller_impl.cc

@@ -252,10 +252,9 @@ void ThreadControllerImpl::DoWork(WorkType work_type) {
   LazyNow lazy_now_after_work(time_source_);
   absl::optional<WakeUp> next_wake_up =
       sequence_->GetPendingWakeUp(&lazy_now_after_work);
-  // The OnSystemIdle callback allows the TimeDomains to advance virtual time
-  // in which case we now have immediate work to do.
-  if ((next_wake_up && next_wake_up->is_immediate()) ||
-      sequence_->OnSystemIdle()) {
+  // The OnIdle() callback allows the TimeDomains to advance virtual time in
+  // which case we now have immediate work to do.
+  if ((next_wake_up && next_wake_up->is_immediate()) || sequence_->OnIdle()) {
     // The next task needs to run immediately, post a continuation if
     // another thread didn't get there first.
     if (work_deduplicator_.DidCheckForMoreWork(

base/task/sequence_manager/thread_controller_with_message_pump_impl.cc

@@ -573,9 +573,9 @@ bool ThreadControllerWithMessagePumpImpl::DoIdleWork() {
   }
 #endif  // BUILDFLAG(IS_WIN)
 
-  if (main_thread_only().task_source->OnSystemIdle()) {
-    // The OnSystemIdle() callback resulted in more immediate work, so schedule
-    // a DoWork callback. For some message pumps returning true from here is
+  if (main_thread_only().task_source->OnIdle()) {
+    // The OnIdle() callback resulted in more immediate work, so schedule a
+    // DoWork callback. For some message pumps returning true from here is
     // sufficient to do that but not on mac.
     pump_->ScheduleWork();
     return false;

base/task/sequence_manager/thread_controller_with_message_pump_impl_unittest.cc

@@ -181,7 +181,7 @@ class FakeSequencedTaskSource : public SequencedTaskSource {
     has_pending_high_resolution_tasks = state;
   }
 
-  bool OnSystemIdle() override { return false; }
+  bool OnIdle() override { return false; }
 
   void MaybeEmitTaskDetails(perfetto::EventContext& ctx,
                             const SelectedTask& selected_task) const override {}