LibWeb: Use CSS Pixels for viewport rects

Author: https://github.com/AtkinsSJ
Commit: 4084c66ad2
Pull-request: https://github.com/SerenityOS/serenity/pull/16514
Reviewed-by: https://github.com/MacDue
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/CSS/StyleComputer.cpp

@@ -1437,10 +1437,10 @@ void StyleComputer::invalidate_rule_cache()
     m_rule_cache = nullptr;
 }
 
-Gfx::IntRect StyleComputer::viewport_rect() const
+CSSPixelRect StyleComputer::viewport_rect() const
 {
     if (auto const* browsing_context = document().browsing_context())
-        return browsing_context->viewport_rect().to_type<float>().to_type<int>();
+        return browsing_context->viewport_rect();
     return {};
 }