getDebugID = function (inst) {
	    if (!inst._debugID) {
	      // Check for ART-like instances. TODO: This is silly/gross.
	      var internal;
	      if (internal = ReactInstanceMap.get(inst)) {
	        inst = internal;
	      }
	    }
	    return inst._debugID;
	  }
Provides common functionality for components that must reconcile multiple
children. This is used by `ReactDOMComponent` to mount, update, and
unmount child components.

@lends {ReactMultiChild.prototype}