IntersectionObserver: second cut.

third_party/WebKit/Source/core/dom/IntersectionObservation.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.
+
+#include "platform/geometry/LayoutRect.h"
+#include "platform/heap/Handle.h"
+
+#ifndef IntersectionObservation_h
+#define IntersectionObservation_h

[dcheng, 2016/01/08 03:02:04]

The include guard should be the first thing.

[szager1, 2016/01/08 05:18:46]

Fixed.  This should probably be a lint error.

+
+namespace blink {
+
+class Element;
+class IntersectionObserver;
+
+class IntersectionObservation : public GarbageCollectedFinalized<IntersectionObservation> {
+public:
+    IntersectionObservation(IntersectionObserver&, Element&, bool shouldReportRootBounds);
+
+    struct IntersectionGeometry {
+        LayoutRect targetRect;
+        LayoutRect intersectionRect;
+        LayoutRect rootRect;
+    };
+
+    IntersectionObserver& observer() const { return *m_observer; }
+    Element* target() const { return m_target.get(); }
+    bool isActive() const { return m_active; }
+    void setActive(bool active) { m_active = active; }
+    unsigned lastThresholdIndex() const { return m_lastThresholdIndex; }
+    void setLastThresholdIndex(unsigned index) { m_lastThresholdIndex = index; }
+    bool shouldReportRootBounds() const { return m_shouldReportRootBounds; }
+
+    void computeIntersectionObservations(double timestamp);
+    void disconnect();
+
+    DECLARE_TRACE();
+
+private:
+    void initializeGeometry(IntersectionGeometry&);
+    void clipToRoot(LayoutRect&);
+    void clipToFrameView(IntersectionGeometry&);
+    bool computeGeometry(IntersectionGeometry&);
+
+    Member<IntersectionObserver> m_observer;
+    WeakPtrWillBeWeakMember<Element> m_target;
+    unsigned m_active : 1;
+    unsigned m_shouldReportRootBounds : 1;
+    unsigned m_lastThresholdIndex : 30;
+};
+
+} // namespace blink
+
+#endif // IntersectionObservation_h