**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
nextProps.hasOwnProperty(propKey) ||
        !lastProps.hasOwnProperty(propKey) ||
        lastProps[propKey] == null
      ) {
        continue;
      }
      if (propKey === STYLE) {
        var lastStyle = lastProps[propKey];
        for (styleName in lastStyle) {
          if (lastStyle.hasOwnProperty(styleName)) {
            if (!styleUpdates) {
              styleUpdates = {};
            }
            styleUpdates[styleName] = '';
          }
        }
      } else if (
        propKey === DANGEROUSLY_SET_INNER_HTML ||
        propKey === CHILDREN
      ) {
        
      } else if (propKey === SUPPRESS_CONTENT_EDITABLE_WARNING) {
        
      } else if (registrationNameModules.hasOwnProperty(propKey)) {
        
        
        
        if (!updatePayload) {