Revert of [scheduler] Change TaskQueue observer call mechanism.

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

Index: third_party/WebKit/Source/platform/scheduler/base/task_queue.h
diff --git a/third_party/WebKit/Source/platform/scheduler/base/task_queue.h b/third_party/WebKit/Source/platform/scheduler/base/task_queue.h
index 8ac280a0fe3aaf8a61290c1bec3a0361878d767c..64c39a6fe75ee22db3736dd16b9a35092f921b45 100644
--- a/third_party/WebKit/Source/platform/scheduler/base/task_queue.h
+++ b/third_party/WebKit/Source/platform/scheduler/base/task_queue.h
@@ -37,9 +37,6 @@
     // Can be called on any thread
     // All methods but SetObserver, SetTimeDomain and GetTimeDomain can be
     // called on |queue|.
-    //
-    // TODO(altimin): Make it base::Optional<base::TimeTicks> to tell
-    // observer about cancellations.
     virtual void OnQueueNextWakeUpChanged(TaskQueue* queue,
                                           base::TimeTicks next_wake_up) = 0;
   };
@@ -165,7 +162,7 @@
 
   // Returns true if the queue has work that's ready to execute now.
   // NOTE: this must be called on the thread this TaskQueue was created by.
-  virtual bool HasTaskToRunImmediately() const = 0;
+  virtual bool HasPendingImmediateWork() const = 0;
 
   // Returns requested run time of next scheduled wake-up for a delayed task
   // which is not ready to run. If there are no such tasks or the queue is