LibHTML: Anonymous blocks *should* inherit some properties

Okay, I got that a bit wrong. Here's what CSS 2.1 says:

"The properties of anonymous boxes are inherited from the enclosing
non-anonymous box. Non-inherited properties have their initial value."

This patch implements a better behavior by only copying the inherited
properties from the parent style.

Libraries/LibHTML/CSS/StyleResolver.cpp

@@ -78,7 +78,7 @@ NonnullRefPtrVector<StyleRule> StyleResolver::collect_matching_rules(const Eleme
     return matching_rules;
 }
 
-static bool is_inherited_property(const StringView& name)
+bool StyleResolver::is_inherited_property(const StringView& name)
 {
     static HashTable<String> inherited_properties;
     if (inherited_properties.is_empty()) {

Libraries/LibHTML/CSS/StyleResolver.h

@@ -22,6 +22,8 @@ public:
 
     NonnullRefPtrVector<StyleRule> collect_matching_rules(const Element&) const;
 
+    static bool is_inherited_property(const StringView&);
+
 private:
     template<typename Callback>
     void for_each_stylesheet(Callback) const;

Libraries/LibHTML/Layout/LayoutBlock.cpp

@@ -1,4 +1,5 @@
 #include <LibGUI/GPainter.h>
+#include <LibHTML/CSS/StyleResolver.h>
 #include <LibHTML/DOM/Element.h>
 #include <LibHTML/Layout/LayoutBlock.h>
 #include <LibHTML/Layout/LayoutInline.h>
@@ -15,7 +16,7 @@ LayoutBlock::~LayoutBlock()
 LayoutNode& LayoutBlock::inline_wrapper()
 {
     if (!last_child() || !last_child()->is_block() || last_child()->node() != nullptr) {
-        append_child(adopt(*new LayoutBlock(nullptr, StyleProperties::create())));
+        append_child(adopt(*new LayoutBlock(nullptr, style_for_anonymous_block())));
     }
     return *last_child();
 }
@@ -236,3 +237,15 @@ HitTestResult LayoutBlock::hit_test(const Point& position) const
     }
     return {};
 }
+
+NonnullRefPtr<StyleProperties> LayoutBlock::style_for_anonymous_block() const
+{
+    auto new_style = StyleProperties::create();
+
+    style().for_each_property([&](auto& name, auto& value) {
+        if (StyleResolver::is_inherited_property(name))
+            new_style->set_property(name, value);
+    });
+
+    return new_style;
+}

Libraries/LibHTML/Layout/LayoutBlock.h

@@ -27,6 +27,8 @@ public:
 private:
     virtual bool is_block() const override { return true; }
 
+    NonnullRefPtr<StyleProperties> style_for_anonymous_block() const;
+
     void layout_inline_children();
     void layout_block_children();