(Regarding the experimental `React.unstable_Profiler` API and reactjs/rfcs/pull/51.)

PR #13058 changed the behavior of React profiling builds to opt host roots into `ProfileMode` if the React DevTools extension is detected. This was necessary in order to have accurate tree base time measurements for the visual flame graphs.

The Profiler plug-in for DevTools does feature detection to determine if it's enabled by looking at each root and seeing if any of the fibers contain an `actualDuration` attribute,

The problem is that the `actualDuration` attribute will be present on v16.4 fibers, which pre-date PR #13058. As a result, the Profiler UI may enable itself with versions of React that it cannot work correctly with.

Perhaps an easy solution would be to rename one of the `unstable_Profiler`'s fiber attributes prior to the next minor release (e.g. `treeBaseTime` -> `treeBaseDuration`) and change the DevTools Profiler to feature check using this new name instead.
currentParent = parent.stateNode.containerInfo;
            currentParentIsContainer = true;
            break findParent;
          case HostPortal:
            currentParent = parent.stateNode.containerInfo;
            currentParentIsContainer = true;
            break findParent;
        }
        parent = parent.return;
      }
      currentParentIsValid = true;
    }
    if (node.tag === HostComponent || node.tag === HostText) {
      commitNestedUnmounts(node);
      
      
      if (currentParentIsContainer) {
        removeChildFromContainer((currentParent: any), node.stateNode);
      } else {
        removeChild((currentParent: any), node.stateNode);
      }
      
    } else if (node.tag === HostPortal) {
      
      
      currentParent = node.stateNode.containerInfo;
      
      if (node.child !== null) {
        node.child.return = node;
        node = node.child;