Revert of Schedule garbage collection on worker threads using idle 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 0e16eb908d0083bc6c3ff695126611973a94876a..e6d67fa01cdacbe3a8d26eee247a1bc54b487237 100644
--- a/Source/core/workers/WorkerThread.h
+++ b/Source/core/workers/WorkerThread.h
@@ -128,12 +128,8 @@
     virtual void destroyIsolate();
     virtual void terminateV8Execution();
 
-    // This is protected virtual for testing.
-    virtual bool doIdleGc(double deadlineSeconds);
-
 private:
     friend class WorkerSharedTimer;
-    friend class WorkerThreadIdleTask;
     friend class WorkerMicrotaskRunner;
 
     void stopInShutdownSequence();
@@ -141,7 +137,7 @@
 
     void initialize();
     void shutdown();
-    void performIdleWork(double deadlineSeconds);
+    void idleHandler();
     void postDelayedTask(PassOwnPtr<ExecutionContextTask>, long long delayMs);
     void postDelayedTask(const WebTraceLocation&, PassOwnPtr<ExecutionContextTask>, long long delayMs);
 
@@ -152,7 +148,6 @@
 
     RefPtr<WorkerLoaderProxy> m_workerLoaderProxy;
     WorkerReportingProxy& m_workerReportingProxy;
-    RawPtr<WebScheduler> m_webScheduler; // Not owned.
 
     RefPtrWillBePersistent<WorkerInspectorController> m_workerInspectorController;
     Mutex m_workerInspectorControllerMutex;