DevTools: More code reduce via using document.createElementWithClass and document.createChild.

Source/devtools/front_end/ui/SettingsUI.js

 /*
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 97 matching lines @@
         inputElement.style.width = width;
     inputElement.placeholder = placeholder || "";
 
     if (validatorCallback || instant) {
         inputElement.addEventListener("change", onInput, false);
         inputElement.addEventListener("input", onInput, false);
     }
     inputElement.addEventListener("keydown", onKeyDown, false);
 
     var errorMessageLabel;
-    if (validatorCallback) {
-        errorMessageLabel = p.createChild("div");
-        errorMessageLabel.classList.add("field-error-message");
-    }
+    if (validatorCallback)
+        errorMessageLabel = p.createChild("div", "field-error-message");
 
     function onInput()
     {
         if (validatorCallback)
             validate();
         if (instant)
             apply();
     }
 
     function onKeyDown(event)
@@ skipping 41 matching lines @@
 }
 
 /**
  * @param {string} name
  * @param {!Element} element
  * @return {!Element}
  */
 WebInspector.SettingsUI.createCustomSetting = function(name, element)
 {
     var p = document.createElement("p");
-    var fieldsetElement = document.createElement("fieldset");
+    var fieldsetElement = p.createChild("fieldset");
     fieldsetElement.createChild("label").textContent = name;
     fieldsetElement.appendChild(element);
-    p.appendChild(fieldsetElement);
     return p;
 }
 
 /**
  * @param {!WebInspector.Setting} setting
  * @return {!Element}
  */
 WebInspector.SettingsUI.createSettingFieldset = function(setting)
 {
     var fieldset = document.createElement("fieldset");
@@ skipping 61 matching lines @@
 
 WebInspector.UISettingDelegate.prototype = {
     /**
      * @return {?Element}
      */
     settingElement: function()
     {
         return null;
     }
 }