Generate StyleBoxData in ComputedStyleBase.

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 165 matching lines @@
     // which can be either a keyword or Length, this is specified in this file for now. Remove this
     // once we can support union fields.
     {
       name: "VerticalAlign",
       field_template: "storage_only",
       field_size: 4,
       default_value: "EVerticalAlign::kBaseline",
       type_name: "EVerticalAlign",
     },
     {
+      name: "VerticalAlignLength",
+      field_template: "storage_only",
+      default_value: "Length()",
+      field_type_path: "platform/Length",
+      field_group: "box",
+    },
+    {
       name: "border",
       field_template: "storage_only",
       field_type_path: "core/style/BorderData",
       field_group: "surround",
       default_value: "BorderData()",
     },
     {
       name: "Background",
       field_template: "storage_only",
       field_type_path: "core/style/FillLayer",
@@ skipping 16 matching lines @@
       field_group: "visual",
     },
     {
       name: "HasAutoClip",
       field_template: "storage_only",
       type_name: "bool",
       field_size: 1,
       default_value: "true",
       field_group: "visual",
     },
+    {
+      name: "HasAutoZIndex",
+      field_template: "storage_only",
+      type_name: "bool",
+      field_size: 1,
+      field_group: "box",
+      default_value: "true",
+    },
+    {
+      name: "BoxDecorationBreak",
+      field_template: "storage_only",
+      type_name: "EBoxDecorationBreak",
+      field_size: 1,
+      field_group: "box",
+      default_value: "EBoxDecorationBreak::kSlice",
+    },
+    {
+      name: "BoxSizing",
+      field_template: "storage_only",
+      type_name: "EBoxSizing",
+      field_size: 1,
+      field_group: "box",
+      default_value: "EBoxSizing::kContentBox",
+    },
   ],
 }