[Reland] Dont post delayed DoWork for disabled queues.

third_party/WebKit/public/platform/scheduler/base/task_queue.h

Index: third_party/WebKit/public/platform/scheduler/base/task_queue.h
diff --git a/third_party/WebKit/public/platform/scheduler/base/task_queue.h b/third_party/WebKit/public/platform/scheduler/base/task_queue.h
index 07335fb002075f01235ba86c2300d30cfe4e7df9..c57d23737a45a6631b7991d86b23c51ebe1f14ea 100644
--- a/third_party/WebKit/public/platform/scheduler/base/task_queue.h
+++ b/third_party/WebKit/public/platform/scheduler/base/task_queue.h
@@ -150,8 +150,9 @@ class BLINK_PLATFORM_EXPORT TaskQueue : public base::SingleThreadTaskRunner {
   // NOTE: this must be called on the thread this TaskQueue was created by.
   virtual bool HasPendingImmediateWork() const = 0;
 
-  // Returns requested run time of next delayed task, which is not ready
-  // to run. If there are no such tasks, returns base::nullopt.
+  // Returns requested run time of next scheduled wakeup for a delayed task
+  // which is not ready to run. If there are no such tasks or the queue is
+  // disabled (by a QueueEnabledVoter) it returns base::nullopt.
   // NOTE: this must be called on the thread this TaskQueue was created by.
   virtual base::Optional<base::TimeTicks> GetNextScheduledWakeUp() = 0;