scheduler: Post high priority tasks directly to the message loop

Source/platform/scheduler/Scheduler.h

Index: Source/platform/scheduler/Scheduler.h
diff --git a/Source/platform/scheduler/Scheduler.h b/Source/platform/scheduler/Scheduler.h
index 7f7835abcf76d6ac90c6780e6fdad520e3808d80..bea3881c77f66123540e089e3fe7d522e6d5a8d0 100644
--- a/Source/platform/scheduler/Scheduler.h
+++ b/Source/platform/scheduler/Scheduler.h
@@ -75,6 +75,7 @@ protected:
 
     void scheduleIdleTask(const TraceLocation&, const IdleTask&);
     void postHighPriorityTaskInternal(const TraceLocation&, const Task&, const char* traceName);
+    void didRunHighPriorityTask();
 
     static void sharedTimerAdapter();
 
@@ -84,20 +85,12 @@ protected:
     bool runPendingHighPriorityTasksIfInCompositorPriority();
 
     // Returns true if any work was done.
-    bool swapQueuesAndRunPendingTasks();
-
-    void swapQueuesRunPendingTasksAndAllowHighPriorityTaskRunnerPosting();
-
-    // Returns true if any work was done.
     bool executeHighPriorityTasks(Deque<TracedTask>&);
 
     // Return the current SchedulerPolicy.
     SchedulerPolicy schedulerPolicy() const;
 
-    void maybeEnterNormalSchedulerPolicy();
-
-    // Must be called while m_pendingTasksMutex is locked.
-    void maybePostMainThreadPendingHighPriorityTaskRunner();
+    void updatePolicy();
 
     void tickSharedTimer();
 
@@ -115,10 +108,8 @@ protected:
 
     WebThread* m_mainThread;
 
-    // This mutex protects calls to the pending task queue, m_highPriorityTaskRunnerPosted and
-    // m_compositorPriorityPolicyEndTimeSeconds.
+    // This mutex protects m_compositorPriorityPolicyEndTimeSeconds.
     Mutex m_pendingTasksMutex;
-    DoubleBufferedDeque<TracedTask> m_pendingHighPriorityTasks;
     double m_compositorPriorityPolicyEndTimeSeconds;
 
     // Declared volatile as it is atomically incremented.