Initial ResizeObserver implementation

third_party/WebKit/Source/core/observer/ResizeObservation.h

+// Copyright 2016 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 ResizeObservation_h
+#define ResizeObservation_h
+
+#include "core/observer/ResizeObserverEntry.h"
+#include "platform/geometry/LayoutSize.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class Element;
+class ResizeObserver;
+
+// ResizeObservation represents an element that is being observed.
+class ResizeObservation : public GarbageCollected<ResizeObservation> {
+public:
+    ResizeObservation(Element* target, ResizeObserver*);
+
+    // True if target was resized since last broadcast
+    bool hasResized() const;
+
+    Element* target() const { return m_target; }
+
+    LayoutSize broadcastSize() const { return m_broadcastSize; }
+
+    void setBroadcastSize(const LayoutSize& size) { m_broadcastSize = size; }
+
+    DECLARE_TRACE();
+
+private:
+
+    WeakMember<Element> m_target;
+    // m_observer only purpose is to maintain a strong reference
+    // to the ResizeObserver, to prevent it from being garbage-collected.
+    Member<ResizeObserver> m_observer;
+    LayoutSize m_broadcastSize;
+};
+
+
+
+} // namespace blink
+
+#endif // ResizeObservation_h