**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
break;
      case 'textarea':
        lastProps = ReactDOMFiberTextarea.getHostProps(
          domElement,
          lastRawProps,
        );
        nextProps = ReactDOMFiberTextarea.getHostProps(
          domElement,
          nextRawProps,
        );
        updatePayload = [];
        break;
      default:
        lastProps = lastRawProps;
        nextProps = nextRawProps;
        if (
          typeof lastProps.onClick !== 'function' &&
          typeof nextProps.onClick === 'function'
        ) {
          
          trapClickOnNonInteractiveElement(((domElement: any): HTMLElement));
        }
        break;
    }
    assertValidProps(tag, nextProps, getCurrentFiberOwnerName);
    var propKey;
    var styleName;
    var styleUpdates = null;
    for (propKey in lastProps) {
      if (