Adds a CancellableTaskFactory and exposes postLoadingTasks to Blink

Source/platform/scheduler/ClosureRunnerTask.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ClosureRunnerTask_h
+#define ClosureRunnerTask_h
+
+#include "platform/PlatformExport.h"
+#include "public/platform/WebThread.h"
+#include "wtf/Functional.h"
+#include "wtf/Noncopyable.h"
+#include "wtf/OwnPtr.h"
+#include "wtf/PassOwnPtr.h"
+
+namespace blink {
+
+class PLATFORM_EXPORT ClosureRunnerTask : public WebThread::Task {
+    WTF_MAKE_NONCOPYABLE(ClosureRunnerTask);
+
+public:
+    explicit ClosureRunnerTask(PassOwnPtr<Closure> closure)
+        : m_closure(closure)
+    {
+    }
+
+    ~ClosureRunnerTask() override { }
+
+    // WebThread::Task implementation.
+    void run() override;
+
+private:
+    OwnPtr<Closure> m_closure;
+};
+
+} // namespace blink
+
+#endif // ClosureRunnerTask_h