Unfork Lazy Component Branches (#13902)

* Introduce elementType field

This will be used to store the wrapped type of an element. E.g. pure and
lazy.

The existing type field will be used for the unwrapped type within them.

* Store the unwrapped type on the type field of lazy components

* Use the raw tags for lazy components

Instead, we check if the elementType and type are equal to test if
we need to resolve props. This is slightly slower in the normal case
but will yield less code and branching.

* Clean up lazy branches

* Collapse work tag numbering

* Split IndeterminateComponent out from Lazy

This way we don't have to check the type in a hacky way in the
indeterminate path. Also, lets us deal with lazy that resolves to
indeterminate and such.

* Missing clean up in rebase

Author: sebmarkbage

src/ReactTestRenderer.js

@@ -17,9 +17,7 @@ import {findCurrentFiberUsingSlowPath} from 'react-reconciler/reflection';
 import {
   Fragment,
   FunctionComponent,
-  FunctionComponentLazy,
   ClassComponent,
-  ClassComponentLazy,
   HostComponent,
   HostPortal,
   HostText,
@@ -29,9 +27,7 @@ import {
   Mode,
   ForwardRef,
   Profiler,
-  ForwardRefLazy,
   PureComponent,
-  PureComponentLazy,
 } from 'shared/ReactWorkTags';
 import invariant from 'shared/invariant';
 import ReactVersion from 'shared/ReactVersion';
@@ -169,17 +165,6 @@ function toTree(node: ?Fiber) {
         instance: node.stateNode,
         rendered: childrenToTree(node.child),
       };
-    case ClassComponentLazy: {
-      const thenable = node.type;
-      const type = thenable._reactResult;
-      return {
-        nodeType: 'component',
-        type,
-        props: {...node.memoizedProps},
-        instance: node.stateNode,
-        rendered: childrenToTree(node.child),
-      };
-    }
     case FunctionComponent:
       return {
         nodeType: 'component',
@@ -188,17 +173,6 @@ function toTree(node: ?Fiber) {
         instance: null,
         rendered: childrenToTree(node.child),
       };
-    case FunctionComponentLazy: {
-      const thenable = node.type;
-      const type = thenable._reactResult;
-      return {
-        nodeType: 'component',
-        type: type,
-        props: {...node.memoizedProps},
-        instance: node.stateNode,
-        rendered: childrenToTree(node.child),
-      };
-    }
     case HostComponent: {
       return {
         nodeType: 'host',
@@ -216,9 +190,7 @@ function toTree(node: ?Fiber) {
     case Mode:
     case Profiler:
     case ForwardRef:
-    case ForwardRefLazy:
     case PureComponent:
-    case PureComponentLazy:
       return childrenToTree(node.child);
     default:
       invariant(
@@ -231,14 +203,10 @@ function toTree(node: ?Fiber) {
 
 const validWrapperTypes = new Set([
   FunctionComponent,
-  FunctionComponentLazy,
   ClassComponent,
-  ClassComponentLazy,
   HostComponent,
   ForwardRef,
-  ForwardRefLazy,
   PureComponent,
-  PureComponentLazy,
   // Normally skipped, but used when there's more than one root child.
   HostRoot,
 ]);