IntersectionObserver: second cut.

third_party/WebKit/Source/core/dom/IntersectionObservation.h

Index: third_party/WebKit/Source/core/dom/IntersectionObservation.h
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObservation.h b/third_party/WebKit/Source/core/dom/IntersectionObservation.h
new file mode 100644
index 0000000000000000000000000000000000000000..75e4570ae5f173a5c80eaaaeea7aaf1e296dd8dd
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/IntersectionObservation.h
@@ -0,0 +1,56 @@
+// 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.
+
+#include "platform/geometry/LayoutRect.h"
+#include "platform/heap/Handle.h"
+
+#ifndef IntersectionObservation_h
+#define IntersectionObservation_h
+
+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;
+    };
+
+    const IntersectionObserver* observer() const { return m_observer; }
+    IntersectionObserver* observer() { return m_observer; }
+    const Element* target() const { return m_target.get(); }
+    Element* target() { return m_target.get(); }
+    bool isActive() const { return m_active; }
+    void setActive(bool active) { m_active = active ? 1 : 0; }

[esprehn, 2015/12/17 01:40:28]

no need for the ternary, you can just assign the bool to the bitfield

[szager1, 2015/12/17 20:27:25]

Done.

+    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