LibHTML: Get rid of the style tree

We now create a layout tree directly from the DOM tree.
This way we don't actually lose text nodes ^)

Libraries/LibHTML/CSS/StyleProperties.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <AK/HashMap.h>
+#include <AK/NonnullRefPtr.h>
+#include <LibHTML/CSS/StyleValue.h>
+
+class StyleProperties {
+public:
+    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);
+    Optional<NonnullRefPtr<StyleValue>> property(const String& name) const;
+
+    Length length_or_fallback(const StringView& property_name, const Length& fallback) const;
+
+private:
+    HashMap<String, NonnullRefPtr<StyleValue>> m_property_values;
+};