LibWeb: Move CSS::CalculationResolutionContext to its own file

This struct will be used within CSSStyleValue.h in a future commit and
having it in CalculatedStyleValue.h causes a dependency loop.

Libraries/LibWeb/CSS/CSSStyleValue.h

@@ -20,6 +20,7 @@
 #include <LibGfx/Color.h>
 #include <LibJS/Heap/Cell.h>
 #include <LibURL/URL.h>
+#include <LibWeb/CSS/CalculationResolutionContext.h>
 #include <LibWeb/CSS/Keyword.h>
 #include <LibWeb/CSS/Length.h>
 #include <LibWeb/CSS/SerializationMode.h>

Libraries/LibWeb/CSS/CalculationResolutionContext.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2025, Callum Law <callumlaw1709@outlook.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/CSS/Angle.h>
+#include <LibWeb/CSS/Frequency.h>
+#include <LibWeb/CSS/Length.h>
+#include <LibWeb/CSS/Time.h>
+
+namespace Web::CSS {
+
+struct CalculationResolutionContext {
+    Variant<Empty, Angle, Frequency, Length, Time> percentage_basis {};
+    Optional<Length::ResolutionContext> length_resolution_context;
+};
+
+}

Libraries/LibWeb/CSS/StyleValues/CalculatedStyleValue.h

@@ -31,11 +31,6 @@ struct CalculationContext {
     Optional<ValueType> percentages_resolve_as {};
     bool resolve_numbers_as_integers = false;
 };
-// Contains the context for resolving the calculation.
-struct CalculationResolutionContext {
-    Variant<Empty, Angle, Frequency, Length, Time> percentage_basis {};
-    Optional<Length::ResolutionContext> length_resolution_context;
-};
 
 class CalculatedStyleValue : public CSSStyleValue {
 public: