Generate getters/setters for VisitedLinkColor.

third_party/WebKit/Source/core/css/ComputedStyleExtraFields.json5

 {
 // This file specifies fields in ComputedStyle that we would like to
 // generate, but are not CSS properties.
 
   parameters: {
     // If the field has_custom_compare_and_copy, then it does not appear in
     // ComputedStyle::operator== and ComputedStyle::CopyNonInheritedFromCached.
     has_custom_compare_and_copy: {
       default: false,
     },
@@ skipping 235 matching lines @@
       name: "color",
       inherited: true,
       field_template: "storage_only",
       field_type_path: "platform/graphics/Color",
       field_group: "inherited",
       default_value: "Color::kBlack",
     },
     {
       name: "VisitedLinkColor",
       inherited: true,
-      field_template: "storage_only",
+      field_template: "external",
       field_type_path: "platform/graphics/Color",
       field_group: "inherited",
       default_value: "Color::kBlack",
     },
     {
       name: "TextAutosizingMultiplier",
       inherited: true,
       field_template: "storage_only",
       type_name: "float",
       field_group: "inherited",
       default_value: "1.0",
     },
   ],
 }