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 CallbackType {

[Sami, 2015/08/11 18:03:00]

nit: enum class?

[rmcilroy, 2015/08/12 14:17:30]

Done.

+        CalledWhenIdle,
+        CalledByTimeout
+    };
+
+    DEFINE_INLINE_TRACE() {}
+    static IdleCallbackDeadline* create(double deadline, CallbackType callbackType, const DocumentLoadTiming& timing)

[Sami, 2015/08/11 18:03:00]

nit: deadlineMillis (here and below)

[rmcilroy, 2015/08/12 14:17:30]

Done.

+    {
+        return new IdleCallbackDeadline(deadline, callbackType, timing);
+    }
+
+    double deadline() const
+    {
+        return m_deadline;
+    }
+
+    bool didTimeout() const
+    {
+        return m_callbackType == CalledByTimeout;
+    }
+
+    bool isExceeded() const;
+
+private:
+    IdleCallbackDeadline(double deadline, CallbackType, const DocumentLoadTiming&);
+
+    double m_deadline;
+    CallbackType m_callbackType;
+    const DocumentLoadTiming& m_timing;
+};
+}
+
+#endif // IdleCallbackDeadline_h