LibWeb: Make box-shadow known throughout the CSS subsystem

This patch spreads box-shadows around:
- The Values important to box-shadows are stored in a BoxShadowData
  struct
- StyleProperties knows how to construct such a struct from a
  BoxShadowStyleValue and a Node knows how to ask for it
- CalculatedValues contain BoxShadowData and expose them

1 files changed, 14 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp b/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
index 0adb41aad6..84ea18d5d7 100644
--- a/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
+++ b/Userland/Libraries/LibWeb/CSS/StyleProperties.cpp
@@ -764,4 +764,18 @@ Optional<CSS::Repeat> StyleProperties::background_repeat_y() const
         return {};
     }
 }
+
+Optional<CSS::BoxShadowData> StyleProperties::box_shadow() const
+{
+    auto value_or_error = property(CSS::PropertyID::BoxShadow);
+    if (!value_or_error.has_value())
+        return {};
+
+    auto value = value_or_error.value();
+    if (!value->is_box_shadow())
+        return {};
+
+    auto box = verify_cast<CSS::BoxShadowStyleValue>(value.ptr());
+    return { { box->offset_x(), box->offset_y(), box->blur_radius(), box->color() } };
+}
 }