Convert more this.exports to module.exports

sky/framework/inspector/css-agent.sky

 <script>
 function CSS(domAgent) {
   this.domAgent_ = domAgent;
 }
 
 CSS.prototype.enable = function() {
 };
 
 CSS.prototype.getInlineStylesForNode = function(params) {
   return {
@@ skipping 29 matching lines @@
     computedStyles.push({
       "name": name,
       "value": style.getPropertyValue(name),
     });
   }
   return {
     "computedStyle": computedStyles,
   }
 }
 
-this.exports = CSS;
+module.exports = CSS;
 </script>