**Do you want to request a *feature* or report a *bug*?**
*Feature*

**What is the current behavior?**
In Firefox the `dialog` element is not implemented. We use a polyfill to be able to support it. Everything works well. But React warns that the `dialog` element is unrecognized, and this on each page load, which is quite useless (for this specific case).
I would like the possibility to disable the  warning but only for some elements. So the utility of this warning remains when the developer mistype the component name.

**What is the expected behavior?**
Once we specified which tag are "accepted/normal" React will not warn on specified unrecognized tags.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
React 16
Firefox 57

In previous versions there was no warning.

Is this clear enough? Do you need any other information?
Cheers
* @providesModule ReactDOMFiberComponent
 * @flow
 */
'use strict';
var CSSPropertyOperations = require('CSSPropertyOperations');
var DOMNamespaces = require('DOMNamespaces');
var DOMProperty = require('DOMProperty');
var DOMPropertyOperations = require('DOMPropertyOperations');
var EventPluginRegistry = require('EventPluginRegistry');
var ReactBrowserEventEmitter = require('ReactBrowserEventEmitter');
var ReactDOMFiberInput = require('ReactDOMFiberInput');
var ReactDOMFiberOption = require('ReactDOMFiberOption');
var ReactDOMFiberSelect = require('ReactDOMFiberSelect');
var ReactDOMFiberTextarea = require('ReactDOMFiberTextarea');
var {getCurrentFiberOwnerName} = require('ReactDebugCurrentFiber');
var {DOCUMENT_NODE, DOCUMENT_FRAGMENT_NODE} = require('HTMLNodeType');
var assertValidProps = require('assertValidProps');
var emptyFunction = require('fbjs/lib/emptyFunction');
var inputValueTracking = require('inputValueTracking');
var isCustomComponent = require('isCustomComponent');
var setInnerHTML = require('setInnerHTML');
var setTextContent = require('setTextContent');
if (__DEV__) {
  var warning = require('fbjs/lib/warning');
  var {getCurrentFiberStackAddendum} = require('ReactDebugCurrentFiber');
  var ReactDOMInvalidARIAHook = require('ReactDOMInvalidARIAHook');
  var ReactDOMNullInputValuePropHook = require('ReactDOMNullInputValuePropHook');
  var ReactDOMUnknownPropertyHook = require('ReactDOMUnknownPropertyHook');
  var {validateProperties: validateARIAProperties} = ReactDOMInvalidARIAHook;
  var {