LibHTML: Add a LayoutStyle object (computed style for a LayoutNode.)

LibHTML/Layout/LayoutStyle.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <SharedGraphics/Color.h>
+
+struct Box {
+    int top { 0 };
+    int right { 0 };
+    int bottom { 0 };
+    int left { 0 };
+};
+
+enum FontStyle {
+    Normal,
+    Bold,
+};
+
+class LayoutStyle {
+public:
+    LayoutStyle();
+    ~LayoutStyle();
+
+    Color text_color() const { return m_text_color; }
+    Color background_color() const { return m_background_color; }
+
+    Box& offset() { return m_offset; }
+    Box& margin() { return m_margin; }
+    Box& padding() { return m_padding; }
+
+    const Box& offset() const { return m_offset; }
+    const Box& margin() const { return m_margin; }
+    const Box& padding() const { return m_padding; }
+
+    FontStyle font_style() const { return m_font_style; }
+
+private:
+    Color m_text_color;
+    Color m_background_color;
+
+    Box m_offset;
+    Box m_margin;
+    Box m_padding;
+
+    FontStyle m_font_style { FontStyle::Normal };
+};