Rewrite Shadow DOM distribution engine to support partial synchronous distribution for v1

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

Index: third_party/WebKit/Source/core/dom/DocumentOrderedList.h
diff --git a/third_party/WebKit/Source/core/dom/DocumentOrderedList.h b/third_party/WebKit/Source/core/dom/DocumentOrderedList.h
index 225d8263e6ed2e4628c1dfd00d2469d7175de596..e79726b57b6ea813b574529828e0442152cb73af 100644
--- a/third_party/WebKit/Source/core/dom/DocumentOrderedList.h
+++ b/third_party/WebKit/Source/core/dom/DocumentOrderedList.h
@@ -43,16 +43,21 @@ public:
 
     void add(Node*);
     void remove(const Node*);
+    bool contains(const Node* node) const { return m_nodes.contains(const_cast<Node*>(node)); };
     bool isEmpty() const { return m_nodes.isEmpty(); }
     void clear() { m_nodes.clear(); }
     size_t size() const { return m_nodes.size(); }
 
     using iterator = HeapListHashSet<Member<Node>, 32>::iterator;
+    using const_iterator = HeapListHashSet<Member<Node>, 32>::const_iterator;
     using const_reverse_iterator = HeapListHashSet<Member<Node>, 32>::const_reverse_iterator;
 
     iterator begin() { return m_nodes.begin(); }
     iterator end() { return m_nodes.end(); }
 
+    const_iterator begin() const { return m_nodes.begin(); }
+    const_iterator end() const { return m_nodes.end(); }
+
     const_reverse_iterator rbegin() const { return m_nodes.rbegin(); }
     const_reverse_iterator rend() const { return m_nodes.rend(); }