[Blink-Worker] WorkerThread fires idleHandler only at the end of processing all tasks.

Source/core/workers/WorkerThread.h

Index: Source/core/workers/WorkerThread.h
diff --git a/Source/core/workers/WorkerThread.h b/Source/core/workers/WorkerThread.h
index f1d083b1e768abdcbf4f0daa9be2c5610adc4de9..c3210df38e468b87322017e17d2305fd342799e6 100644
--- a/Source/core/workers/WorkerThread.h
+++ b/Source/core/workers/WorkerThread.h
@@ -58,6 +58,33 @@ enum WorkerThreadStartMode {
 };
 
 class WorkerThread : public RefCounted<WorkerThread> {
+
+    class WorkerThreadTask : public blink::WebThread::Task {
+    WTF_MAKE_NONCOPYABLE(WorkerThreadTask); WTF_MAKE_FAST_ALLOCATED;
+    public:
+        static PassOwnPtr<WorkerThreadTask> create(WorkerThread&
+        , PassOwnPtr<ExecutionContextTask>, bool);
+
+        virtual ~WorkerThreadTask() { }
+        virtual void run() override;
+
+        void setIsIdleHandlerTask(bool isIdleHandlerTask) { m_isIdleHandlerTask = isIdleHandlerTask; }
+        bool isIdleHandlerTask() const { return m_isIdleHandlerTask; }
+        void cancelTask() { m_isTaskCanceled = true; };
+        double creationTimeStamp() const { return m_timeStamp; }
+
+    private:
+        WorkerThreadTask(WorkerThread&, PassOwnPtr<ExecutionContextTask>, bool);
+
+        WorkerThread& m_workerThread;
+        OwnPtr<ExecutionContextTask> m_task;
+        bool m_isInstrumented;
+        bool m_isIdleHandlerTask;
+        bool m_isTaskCanceled;
+        // Creation time stamp
+        double m_timeStamp;
+    };
+
 public:
     virtual ~WorkerThread();
 
@@ -98,6 +125,10 @@ public:
     void setWorkerInspectorController(WorkerInspectorController*);
 
 protected:
+    int decrementAndReturnTaskCount();
+    void queueUpIdleHandlerNow(long long delayMs);
+    int taskCount() { return m_tasksCount; }
+
     WorkerThread(WorkerLoaderProxy&, WorkerReportingProxy&, PassOwnPtrWillBeRawPtr<WorkerThreadStartupData>);
 
     // Factory method for creating a new worker context for the thread.
@@ -116,6 +147,8 @@ private:
     void cleanup();
     void idleHandler();
     void postDelayedTask(PassOwnPtr<ExecutionContextTask>, long long delayMs);
+    // Method returns true if the task is canceled & cleared, else returns false
+    inline bool clearIdleHandlerTaskIfSet();
 
     bool m_terminated;
     OwnPtr<WorkerSharedTimer> m_sharedTimer;
@@ -138,6 +171,9 @@ private:
     // Used to signal thread termination.
     OwnPtr<WebWaitableEvent> m_terminationEvent;
 
+    WorkerThreadTask* m_lastQueuedIdleHandlerTask;
+    volatile int m_tasksCount;
+
     // FIXME: This has to be last because of crbug.com/401397 - the
     // WorkerThread might get deleted before it had a chance to properly
     // shut down. By deleting the WebThread first, we can guarantee that