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

**What is the current behavior?**
In mobile Safari, DOM events originating from elements rendered through a Portal do **not** bubble (propagate) up the React component tree.

**If the current behavior is a bug, please provide the steps to reproduce....**
Please see the following JSFiddle: https://jsfiddle.net/zebulonj/wf7orwan/

In this JSFiddle, the expected behavior (seen in a desktop browser) is that clicking on the portal content (appearing as a modal, including backdrop) should toggle to the "On" or "Off" indicator rendered in the main content. However, in mobile Safari (iOS 11.1.1), the click events do not propagate.


**What is the expected behavior?**
Click events should propagate up the React component tree.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
Affected: React 16.2
iOS 11.1.1

updatePayload = [];
      break;
    case 'select':
      lastProps = ReactDOMFiberSelect.getHostProps(domElement, lastRawProps);
      nextProps = ReactDOMFiberSelect.getHostProps(domElement, nextRawProps);
      updatePayload = [];
      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);
  let propKey;
  let styleName;
  let styleUpdates = null;
  for (propKey in lastProps) {
    if (