Add the Presentation API module and a single event target

Source/modules/presentation/Presentation.h

+// Copyright 2014 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 Presentation_h
+#define Presentation_h
+
+#include "core/dom/ContextLifecycleObserver.h"
+#include "core/events/EventTarget.h"
+
+namespace blink {
+
+class Presentation FINAL
+    : public RefCountedGarbageCollectedWillBeGarbageCollectedFinalized<Presentation>
+    , public EventTargetWithInlineData
+    , ContextLifecycleObserver {

[Peter Beverloo, 2014/09/12 12:22:09]

Please indicate visibility of this parent class.

[whywhat, 2014/09/12 15:01:14]

Done.

+    DEFINE_EVENT_TARGET_REFCOUNTING_WILL_BE_REMOVED(RefCountedGarbageCollected<Presentation>);
+    DEFINE_WRAPPERTYPEINFO();
+public:

[Peter Beverloo, 2014/09/12 12:22:09]

Do you need WILL_BE_USING_GARBAGE_COLLECTED_MIXIN() here?

[whywhat, 2014/09/12 15:01:14]

I believe I do. At least to be consistent with other Navigator* objects like
Battery/Geolocation/etc.

+    static Presentation* create(ExecutionContext*);
+    virtual ~Presentation();
+
+    // EventTarget implementation.
+    virtual const AtomicString& interfaceName() const OVERRIDE;
+    virtual ExecutionContext* executionContext() const OVERRIDE;
+
+    virtual void trace(Visitor*) OVERRIDE;
+
+    DEFINE_ATTRIBUTE_EVENT_LISTENER(availablechange);
+
+private:
+    explicit Presentation(ExecutionContext*);
+};
+
+} // namespace blink
+
+#endif // Presentation_h