Remove TODO for computed style options

Removed TODO comment for private method to prepare options.

Author: asamuzaK

lib/CSSStyleDeclaration.js

@@ -53,10 +53,6 @@ class CSSStyleDeclaration {
     this._priorities = new Map();
     this._values = new Map();
 
-    // TODO: Add private method to prepare options.
-    // Options for computed style.
-    this._computedStyleOpts = null;
-
     if (context) {
       if (context.nodeType === 1) {
         this._ownerNode = context;