function findParent(inst) {
	  // TODO: It may be a good idea to cache this to prevent unnecessary DOM
	  // traversal, but caching is difficult to do correctly without using a
	  // mutation observer to listen for all DOM changes.
	  while (inst._hostParent) {
	    inst = inst._hostParent;
	  }
	  var rootNode = ReactDOMComponentTree.getNodeFromInstance(inst);
	  var container = rootNode.parentNode;
	  return ReactDOMComponentTree.getClosestInstanceFromNode(container);
	}
Find the deepest React component completely containing the root of the
passed-in instance (for use when entire React trees are nested within each
other). If React trees are not nested, returns null.