[scheduler] Change TaskQueue observer call mechanism.

third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc b/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
index 5f11a7462b94ca16ca6c0da8a839e1e189d0a56a..517cdc59499a6c8b02ff92f52d1596680f64467e 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/base/task_queue_impl.cc
@@ -813,8 +813,11 @@ void TaskQueueImpl::EnableOrDisableWithSelector(bool enable) {
     return;
 
   if (enable) {
-    if (HasPendingImmediateWork())
-      NotifyWakeUpChangedOnMainThread(base::TimeTicks());
+    if (HasPendingImmediateWorkWithoutDelayedIncomingQueue() &&
+        main_thread_only().observer) {
+      main_thread_only().observer->OnQueueNextWakeUpChanged(this,
+                                                            base::TimeTicks());
+    }
 
     ScheduleDelayedWorkInTimeDomain(main_thread_only().time_domain->Now());
 
@@ -891,16 +894,34 @@ void TaskQueueImpl::ScheduleDelayedWorkInTimeDomain(base::TimeTicks now) {
   main_thread_only().time_domain->ScheduleDelayedWork(
       this, main_thread_only().delayed_incoming_queue.top().delayed_wake_up(),
       now);
+}
 
-  if (!HasPendingImmediateWork()) {
-    NotifyWakeUpChangedOnMainThread(
-        main_thread_only().delayed_incoming_queue.top().delayed_run_time);
-  }
+void TaskQueueImpl::SetScheduledTimeDomainWakeUp(
+    base::Optional<base::TimeTicks> scheduled_time_domain_wake_up) {
+  main_thread_only().scheduled_time_domain_wake_up =
+      scheduled_time_domain_wake_up;
+
+  if (!scheduled_time_domain_wake_up)
+    return;
+  if (!main_thread_only().observer)
+    return;
+  if (HasPendingImmediateWorkWithoutDelayedIncomingQueue())
+    return;
+
+  main_thread_only().observer->OnQueueNextWakeUpChanged(
+      this, scheduled_time_domain_wake_up.value());
 }
 
-void TaskQueueImpl::NotifyWakeUpChangedOnMainThread(base::TimeTicks wake_up) {
-  if (main_thread_only().observer)
-    main_thread_only().observer->OnQueueNextWakeUpChanged(this, wake_up);
+bool TaskQueueImpl::HasPendingImmediateWorkWithoutDelayedIncomingQueue() {
+  // Any work queue tasks count as immediate work.
+  if (!main_thread_only().delayed_work_queue->Empty() ||
+      !main_thread_only().immediate_work_queue->Empty()) {
+    return true;
+  }
+
+  // Finally tasks on |immediate_incoming_queue| count as immediate work.
+  base::AutoLock lock(immediate_incoming_queue_lock_);
+  return !immediate_incoming_queue().empty();
 }
 
 }  // namespace internal