DevTools: Deleting object property in console would just assign it to undefined.

Source/devtools/front_end/sdk/RemoteObject.js

 /*
  * Copyright (C) 2009 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 68 matching lines @@
     /**
      * @param {boolean} accessorPropertiesOnly
      * @param {function(?Array.<!WebInspector.RemoteObjectProperty>, ?Array.<!WebInspector.RemoteObjectProperty>)} callback
      */
     getAllProperties: function(accessorPropertiesOnly, callback)
     {
         throw "Not implemented";
     },
 
     /**
+     * @param {string} name
+     * @param {function(string=)} callback
+     */
+    deleteProperty: function(name, callback)
+    {
+        throw "Not implemented";
+    },
+
+    /**
      * @param {function(this:Object, ...)} functionDeclaration
      * @param {!Array.<!RuntimeAgent.CallArgument>=} args
      * @param {function(?WebInspector.RemoteObject, boolean=)=} callback
      */
     callFunction: function(functionDeclaration, args, callback)
     {
         throw "Not implemented";
     },
 
     /**
@@ skipping 322 matching lines @@
         {
             if (error || wasThrown) {
                 callback(error || result.description);
                 return;
             }
             callback();
         }
     },
 
     /**
+     * @param {string} name
+     * @param {function(string=)} callback
+     */
+    deleteProperty: function(name, callback)
+    {
+        if (!this._objectId) {
+            callback("Can't delete a property of non-object.");
+            return;
+        }
+
+        var deletePropertyFunction = "function(a) { delete this[a]; return !(a in this); }";
+        this._runtimeAgent.callFunctionOn(this._objectId, deletePropertyFunction, [{ value: name }], true, undefined, undefined, deletePropertyCallback);
+
+        /**
+         * @param {?Protocol.Error} error
+         * @param {!RuntimeAgent.RemoteObject} result
+         * @param {boolean=} wasThrown
+         */
+        function deletePropertyCallback(error, result, wasThrown)
+        {
+            if (error || wasThrown) {
+                callback(error || result.description);
+                return;
+            }
+            if (!result.value)
+                callback("Failed to delete property.");
+            else
+                callback();
+        }
+    },
+
+    /**
      * @param {function(?WebInspector.DOMNode)} callback
      */
     pushNodeToFrontend: function(callback)
     {
         if (this.isNode())
             this._domModel.pushNodeToFrontend(this._objectId, callback);
         else
             callback(null);
     },
 
@@ skipping 525 matching lines @@
             result = functionDeclaration.apply(target, rawArgs);
         } catch (e) {
             result = null;
         }
 
         callback(result);
     },
 
     __proto__: WebInspector.RemoteObject.prototype
 }