Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibHTML/CSS/StyledNode.h

@@ -0,0 +1,61 @@
+#pragma once
+
+#include <AK/HashMap.h>
+#include <AK/NonnullRefPtr.h>
+#include <AK/AKString.h>
+#include <LibHTML/TreeNode.h>
+#include <LibHTML/CSS/StyleValue.h>
+
+class Node;
+
+enum class Display {
+    None,
+    Block,
+    Inline,
+};
+
+class StyledNode : public TreeNode<StyledNode> {
+public:
+    static NonnullRefPtr<StyledNode> create(const Node& node)
+    {
+        return adopt(*new StyledNode(&node));
+    }
+    ~StyledNode();
+
+    const Node* node() const { return m_node; }
+
+    template<typename Callback>
+    inline void for_each_child(Callback callback) const
+    {
+        for (auto* node = first_child(); node; node = node->next_sibling())
+            callback(*node);
+    }
+
+    template<typename Callback>
+    inline void for_each_child(Callback callback)
+    {
+        for (auto* node = first_child(); node; node = node->next_sibling())
+            callback(*node);
+    }
+
+    template<typename Callback>
+    inline void for_each_property(Callback callback) const
+    {
+        for (auto& it : m_property_values)
+            callback(it.key, *it.value);
+    }
+
+    void set_property(const String& name, NonnullRefPtr<StyleValue> value)
+    {
+        m_property_values.set(name, move(value));
+    }
+
+    Display display() const;
+
+protected:
+    explicit StyledNode(const Node*);
+
+private:
+    const Node* m_node { nullptr };
+    HashMap<String, NonnullRefPtr<StyleValue>> m_property_values;
+};