Support the essential part of Shadow DOM v1

third_party/WebKit/Source/core/dom/shadow/SlotAssignment.h

Index: third_party/WebKit/Source/core/dom/shadow/SlotAssignment.h
diff --git a/third_party/WebKit/Source/core/html/HTMLSlotElement.h b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.h
similarity index 76%
copy from third_party/WebKit/Source/core/html/HTMLSlotElement.h
copy to third_party/WebKit/Source/core/dom/shadow/SlotAssignment.h
index beb03d132fe4c8d2782f6b8b9ae1ec29a73647bc..84d0336a52fe4fa52792f1f0d2d675fade05ade9 100644
--- a/third_party/WebKit/Source/core/html/HTMLSlotElement.h
+++ b/third_party/WebKit/Source/core/dom/shadow/SlotAssignment.h
@@ -28,28 +28,30 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef HTMLSlotElement_h
-#define HTMLSlotElement_h
+#ifndef SlotAssignment_h
+#define SlotAssignment_h
 
-#include "core/CoreExport.h"
-#include "core/html/HTMLElement.h"
+#include "platform/heap/Handle.h"
 
 namespace blink {
 
-class CORE_EXPORT HTMLSlotElement final : public HTMLElement {
-    DEFINE_WRAPPERTYPEINFO();
+class HTMLSlotElement;
+class Node;
+class ShadowRoot;
+
+class SlotAssignment final {
 public:
-    static PassRefPtrWillBeRawPtr<HTMLSlotElement> create(Document&);
-    ~HTMLSlotElement() override;
+    SlotAssignment() { }
+    HTMLSlotElement* assignedSlotFor(const Node&) const;
+    void resolveAssignment(const ShadowRoot&);
 
-    DECLARE_VIRTUAL_TRACE();
+    DECLARE_TRACE();
 
 private:
-    HTMLSlotElement(Document&);
-
-    AtomicString m_name;
+    void assign(Node&, HTMLSlotElement&);
+    WillBeHeapHashMap<RawPtrWillBeMember<Node>, RawPtrWillBeMember<HTMLSlotElement>> m_assignment;
 };
 
 } // namespace blink
 
-#endif // HTMLSlotElement_h
+#endif // HTMLSlotAssignment_h