title: Reference to child Views (divs) in ScrollView and FlatList
body: <p>Long story short I'm working on adding TV Support to react-native-web. This allows for the idea of a Touchable having focus and AndroidTV And AppleTV automatically scroll ScrollViews and FlatLists based on the item which has focus.</p>
  
  <p>I have this working fine using scrollToIndex etc but in a few cases I need to get access to the child scroll div of the Scroll or FlatList for reference a FlastList creates a wrapper div that represents the "Window" of the scrollView with an inner div that wraps all the items in the view.</p>
  
  <p>Forgive me first as most of my use cases are scrolling horizontal so I frequently mix up widths/heights then what is the "norm"</p>
  
  <p>Basically I'm trying to find the "idiomatic" react-native way to get a ref to that inner div.  This is for web-only as I'm replicating a native feature. </p>
  
  <pre><code>&lt;div&gt; &lt;-- Container div, width/height is width/height of Scroll View, the "ref" I can get a node from --&gt;
       &lt;div&gt; &lt;--  I Want this "ref" - Inner div, width/height is width/height of all its children, overflows parent with enough items --&gt;
             &lt;div&gt; &lt;-- All the children --&gt;
             &lt;div&gt;
              ....
             &lt;div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I can access the node and have this working using firstChild of the scrollview ref.  This is fine but relies on some consistency of the HTML so it seems "fragile". There are a few methods like 'getScrollableNode' and 'getNativeScrollRef'that seem like they might work but they are either not present or reference the parent node.</p>