LibWeb: Make box content sizes indefinite before intrinsic sizing

When calculating the intrinsic width of a box, we now make its content
width & height indefinite before entering the intrinsic sizing layout.
This ensures that any geometry assigned to the box by its parent
formatting context is ignored.

For intrinsic heights, we only make the content height indefinite.
This is because used content width is a valid (but optional) input
to intrinsic height calculation.

Userland/Libraries/LibWeb/Layout/LayoutState.cpp

@@ -416,4 +416,14 @@ void LayoutState::UsedValues::set_content_y(CSSPixels y)
     offset.set_y(y);
 }
 
+void LayoutState::UsedValues::set_indefinite_content_width()
+{
+    m_has_definite_width = false;
+}
+
+void LayoutState::UsedValues::set_indefinite_content_height()
+{
+    m_has_definite_height = false;
+}
+
 }