(DO NOT LAND) Revert of Generate StyleBackgroundData in ComputedStyleBase.

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

Index: third_party/WebKit/Source/core/css/ComputedStyleExtraFields.json5
diff --git a/third_party/WebKit/Source/core/css/ComputedStyleExtraFields.json5 b/third_party/WebKit/Source/core/css/ComputedStyleExtraFields.json5
index 68e408ab850c5e71eee2c9f48d15d5d91d259541..e0288d6618ec3128cdbbe1f58872bf34852cfd52 100644
--- a/third_party/WebKit/Source/core/css/ComputedStyleExtraFields.json5
+++ b/third_party/WebKit/Source/core/css/ComputedStyleExtraFields.json5
@@ -169,19 +169,5 @@
       field_group: "surround",
       default_value: "BorderData()",
     },
-    {
-      name: "Background",
-      field_template: "storage_only",
-      field_type_path: "core/style/FillLayer",
-      default_value: "FillLayer(kBackgroundFillLayer, true)",
-      field_group: "background",
-    },
-    {
-      name: "BackgroundColor",
-      field_template: "storage_only",
-      field_type_path: "core/css/StyleColor",
-      default_value: "Color::kTransparent",
-      field_group: "background",
-    },
   ],
 }