Implement requestIdleCallback API

Source/core/dom/IdleCallbackDeadline.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 IdleCallbackDeadline_h
+#define IdleCallbackDeadline_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class DocumentLoadTiming;
+
+class IdleCallbackDeadline : public GarbageCollected<IdleCallbackDeadline>, public ScriptWrappable {
+    DEFINE_WRAPPERTYPEINFO();
+
+public:
+    enum class CallbackType {
+        CalledWhenIdle,
+        CalledByTimeout
+    };
+
+    DEFINE_INLINE_TRACE() {}
+    static IdleCallbackDeadline* create(double deadlineMillis, CallbackType callbackType, const DocumentLoadTiming& timing)
+    {
+        return new IdleCallbackDeadline(deadlineMillis, callbackType, timing);
+    }
+
+    double timeRemaining() const;
+
+    bool didTimeout() const
+    {
+        return m_callbackType == CallbackType::CalledByTimeout;
+    }
+
+private:
+    IdleCallbackDeadline(double deadlineMillis, CallbackType, const DocumentLoadTiming&);
+
+    double m_deadlineMillis;
+    CallbackType m_callbackType;
+    const DocumentLoadTiming& m_timing;
+};
+}
+
+#endif // IdleCallbackDeadline_h