Move border-*-width out of BorderValue and store on SurroundData in ComputedStyle instead

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: {
-    // - field_size
-    // Number of bits needed to store this field. Only used for storage_only
-    // fields. If specified, the field will be stored as bit field. Otherwise
-    // it will be stored as a normal data member.
-    field_size: {
-      valid_type: "int",
-    },
-
     // 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,
     },
 
     // The rest is the same as CSSProperties.json5, but the only relevant ones in
     // this file are:
     // name, field_template, field_type_path, default_value, type_name, keyword,
     // inherited
@@ skipping 154 matching lines @@
     },
     {
       name: "BackgroundColor",
       field_template: "storage_only",
       field_type_path: "core/css/StyleColor",
       default_value: "Color::kTransparent",
       field_group: "background",
     },
   ],
 }