Replaced an Update effect in complete phase with a Ref effect

Also removed an unnecessary conditional check and improved a flow cast.

Relates originally to PRs #8646 and #8685

src/renderers/dom/fiber/ReactDOMFiber.js

@@ -57,7 +57,10 @@ findDOMNode._injectFiber(function(fiber: Fiber) {
 type DOMContainerElement = Element & { _reactRootContainer: ?Object };
 
 type Container = Element;
-type Props = { children ?: mixed };
+type Props = {
+  autoFocus ?: boolean,
+  children ?: mixed,
+};
 type Instance = Element;
 type TextInstance = Text;
 
@@ -105,7 +108,7 @@ function shouldAutoFocusHostComponent(
     case 'input':
     case 'select':
     case 'textarea':
-      return !!(props : any).autoFocus;
+      return !!props.autoFocus;
   }
   return false;
 }
@@ -223,9 +226,7 @@ var DOMRenderer = ReactFiberReconciler({
     rootContainerInstance : Container,
     internalInstanceHandle : Object,
   ) : void {
-    if (shouldAutoFocusHostComponent(type, newProps)) {
-      (domElement : any).focus();
-    }
+    ((domElement : any) : HTMLButtonElement | HTMLInputElement | HTMLSelectElement | HTMLTextAreaElement).focus();
   },
 
   commitUpdate(

src/renderers/shared/fiber/ReactFiberCompleteWork.js

@@ -39,6 +39,7 @@ var {
   Fragment,
 } = ReactTypeOfWork;
 var {
+  Ref,
   Update,
 } = ReactTypeOfSideEffect;
 
@@ -233,13 +234,13 @@ module.exports = function<T, P, I, TI, PI, C, CX>(
           // (eg DOM renderer supports auto-focus for certain elements).
           // Make sure such renderers get scheduled for later work.
           if (finalizeInitialChildren(instance, type, newProps, rootContainerInstance)) {
-            workInProgress.effectTag |= Update;
+            markUpdate(workInProgress);
           }
 
           workInProgress.stateNode = instance;
           if (workInProgress.ref) {
             // If there is a ref on a host node we need to schedule a callback
-            markUpdate(workInProgress);
+            workInProgress.effectTag |= Ref;
           }
         }
         return null;