IntersectionObserver: second cut.

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

Index: third_party/WebKit/Source/core/dom/IntersectionObserver.h
diff --git a/third_party/WebKit/Source/core/dom/IntersectionObserver.h b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
new file mode 100644
index 0000000000000000000000000000000000000000..e32ea675d8e8db9052151939e3e74e639d5d9373
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/IntersectionObserver.h
@@ -0,0 +1,76 @@
+// 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 IntersectionObserver_h
+#define IntersectionObserver_h
+
+#include "bindings/core/v8/ScriptWrappable.h"
+#include "core/dom/Element.h"
+#include "core/dom/IntersectionObservation.h"
+#include "core/dom/IntersectionObservationRegistry.h"
+#include "core/dom/IntersectionObserverEntry.h"
+#include "platform/heap/Handle.h"
+#include "wtf/HashSet.h"
+#include "wtf/RefCounted.h"
+#include "wtf/Vector.h"
+
+namespace blink {
+
+class ExceptionState;
+class IntersectionObserverCallback;
+class IntersectionObserverInit;
+
+typedef WillBeHeapVector<RefPtrWillBeRawPtr<IntersectionObserverEntry>> IntersectionObserverEntryVector;
+
+class IntersectionObserver final : public RefCountedWillBeGarbageCollectedFinalized<IntersectionObserver>, public ScriptWrappable {

[haraken, 2015/11/16 00:41:35]

You don't need to use WillBe types.

[szager1, 2015/11/19 19:15:38]

Working on this...

+    DEFINE_WRAPPERTYPEINFO();
+    friend class IntersectionObserverRegistry;
+public:
+    static PassRefPtrWillBeRawPtr<IntersectionObserver> create(const IntersectionObserverInit&, PassOwnPtrWillBeRawPtr<IntersectionObserverCallback>, ExceptionState&);
+    static void resumeSuspendedObservers();
+
+    ~IntersectionObserver();
+
+    bool checkTargetHierarchy(Element*);
+    Document& getTrackingDocumentForTarget(Element*);
+    void observe(Element*, ExceptionState&);
+    void unobserve(Element*, ExceptionState&);
+    void disconnect(IntersectionObservation&);
+    void disconnect();
+    IntersectionObserverEntryVector takeRecords();
+
+    void enqueueIntersectionObserverEntry(PassRefPtrWillBeRawPtr<IntersectionObserverEntry>);
+
+    bool hasRoot() const { return m_hasRoot; }
+    Element* root() { return m_root.get(); }
+    Document* trackingDocument() { return m_trackingDocument.get(); }
+    const Vector<float>& thresholds() const { return m_thresholds; }
+    size_t firstThresholdGreaterThan(float ratio) const;
+    bool shouldBeSuspended() const;
+    void deliver();
+
+    // Eagerly finalized as destructor accesses heap object members.
+    EAGERLY_FINALIZE();

[haraken, 2015/11/16 00:41:35]

I guess you don't need this. The destructor is not touching any on-heap object,
as far as I see.

[szager1, 2015/11/19 19:15:38]

Done.

+    DECLARE_TRACE();
+
+private:
+    explicit IntersectionObserver(PassOwnPtrWillBeRawPtr<IntersectionObserverCallback>, RefPtrWillBeRawPtr<Element>, int, const Vector<float>&);
+
+    PassRefPtr<IntersectionObservation> createObservation(Element*);
+
+    OwnPtrWillBeMember<IntersectionObserverCallback> m_callback;
+    WeakPtrWillBeWeakMember<Element> m_root;
+    WeakPtrWillBeWeakMember<Document> m_trackingDocument;
+    IntersectionObservation::HashSet m_observations;
+    IntersectionObserverEntryVector m_entries;
+    Vector<float> m_thresholds;
+    int m_rootMargin;
+    // m_root is a weak pointer, so may become null if the root Element is deallocated.
+    // Only m_hasRoot indicates for certain that there *should* be a root.
+    bool m_hasRoot;
+};
+
+} // namespace blink
+
+#endif // IntersectionObserver_h