LibWeb: LayoutNodes know whether they are flex-items

This is useful for debugging when dumping the layout tree.

Userland/Libraries/LibWeb/Dump.cpp

@@ -165,7 +165,9 @@ void dump_tree(StringBuilder& builder, const Layout::Node& layout_node, bool sho
         if (box.is_inline_block())
             builder.appendff(" {}inline-block{}", inline_block_color_on, color_off);
         if (box.computed_values().display() == CSS::Display::Flex)
-            builder.appendff(" {}flex{}", flex_color_on, color_off);
+            builder.appendff(" {}flex-container{}", flex_color_on, color_off);
+        if (box.is_flex_item())
+            builder.appendff(" {}flex-item{}", flex_color_on, color_off);
 
         if (show_box_model) {
             // Dump the horizontal box properties

Userland/Libraries/LibWeb/Layout/FlexFormattingContext.cpp

@@ -42,6 +42,8 @@ void FlexFormattingContext::run(Box& box, LayoutMode layout_mode)
     float tallest_child_height = 0;
     float widest_child_width = 0;
     box.for_each_child_of_type<Box>([&](Box& child_box) {
+        child_box.set_flex_item(true);
+
         child_box.set_offset(x, y);
         tallest_child_height = max(tallest_child_height, child_box.height());
         widest_child_width = max(widest_child_width, child_box.width());

Userland/Libraries/LibWeb/Layout/Node.h

@@ -109,6 +109,9 @@ public:
     bool is_absolutely_positioned() const;
     bool is_fixed_position() const;
 
+    bool is_flex_item() const { return m_is_flex_item; }
+    void set_flex_item(bool b) { m_is_flex_item = b; }
+
     const BlockBox* containing_block() const;
     BlockBox* containing_block() { return const_cast<BlockBox*>(const_cast<const Node*>(this)->containing_block()); }
 
@@ -182,6 +185,8 @@ private:
     bool m_visible { true };
     bool m_children_are_inline { false };
     SelectionState m_selection_state { SelectionState::None };
+
+    bool m_is_flex_item { false };
 };
 
 class NodeWithStyle : public Node {