LibWeb: Add resolving calc() to a number/integer/percentage

None of these require any outside metrics, which is nice! I believe the
Values-4 spec would have us simplify them down into a single value at
parse time, but that's a yak for another day.

Userland/Libraries/LibWeb/CSS/StyleValue.cpp

@@ -416,6 +416,30 @@ Optional<LengthPercentage> CalculatedStyleValue::resolve_length_percentage(Layou
         });
 }
 
+Optional<Percentage> CalculatedStyleValue::resolve_percentage() const
+{
+    auto result = m_expression->resolve(nullptr, {});
+    if (result.value().has<Percentage>())
+        return result.value().get<Percentage>();
+    return {};
+}
+
+Optional<float> CalculatedStyleValue::resolve_number()
+{
+    auto result = m_expression->resolve(nullptr, {});
+    if (result.value().has<float>())
+        return result.value().get<float>();
+    return {};
+}
+
+Optional<i64> CalculatedStyleValue::resolve_integer()
+{
+    auto result = m_expression->resolve(nullptr, {});
+    if (result.value().has<float>())
+        return lroundf(result.value().get<float>());
+    return {};
+}
+
 static bool is_number(CalculatedStyleValue::ResolvedType type)
 {
     return type == CalculatedStyleValue::ResolvedType::Number || type == CalculatedStyleValue::ResolvedType::Integer;

Userland/Libraries/LibWeb/CSS/StyleValue.h

@@ -803,6 +803,9 @@ public:
     NonnullOwnPtr<CalcSum> const& expression() const { return m_expression; }
     Optional<Length> resolve_length(Layout::Node const& layout_node) const;
     Optional<LengthPercentage> resolve_length_percentage(Layout::Node const&, Length const& percentage_basis) const;
+    Optional<Percentage> resolve_percentage() const;
+    Optional<float> resolve_number();
+    Optional<i64> resolve_integer();
 
 private:
     explicit CalculatedStyleValue(String const& expression_string, NonnullOwnPtr<CalcSum> calc_sum, ResolvedType resolved_type)