Remove unnecessary ReactMutableSource fork

Author: Brian Vaughn

packages/react-dom/src/client/ReactDOMRoot.js

@@ -29,8 +29,6 @@ export type RootOptions = {
   ...
 };
 
-import {findHostInstanceWithNoPortals} from 'react-reconciler/src/ReactFiberReconciler';
-import {registerMutableSourceForHydration} from 'react-reconciler/src/ReactMutableSource';
 import {
   isContainerMarkedAsRoot,
   markContainerAsRoot,
@@ -48,6 +46,8 @@ import {ensureListeningTo} from './ReactDOMComponent';
 import {
   createContainer,
   updateContainer,
+  findHostInstanceWithNoPortals,
+  registerMutableSourceForHydration,
 } from 'react-reconciler/src/ReactFiberReconciler';
 import invariant from 'shared/invariant';
 import {

packages/react-reconciler/src/ReactFiberReconciler.js

@@ -49,6 +49,7 @@ import {
   findBoundingRects as findBoundingRects_old,
   focusWithin as focusWithin_old,
   observeVisibleRects as observeVisibleRects_old,
+  registerMutableSourceForHydration as registerMutableSourceForHydration_old,
 } from './ReactFiberReconciler.old';
 
 import {
@@ -86,6 +87,7 @@ import {
   findBoundingRects as findBoundingRects_new,
   focusWithin as focusWithin_new,
   observeVisibleRects as observeVisibleRects_new,
+  registerMutableSourceForHydration as registerMutableSourceForHydration_new,
 } from './ReactFiberReconciler.new';
 
 export const createContainer = enableNewReconciler
@@ -186,3 +188,7 @@ export const focusWithin = enableNewReconciler
 export const observeVisibleRects = enableNewReconciler
   ? observeVisibleRects_new
   : observeVisibleRects_old;
+
+export const registerMutableSourceForHydration = enableNewReconciler
+  ? registerMutableSourceForHydration_new
+  : registerMutableSourceForHydration_old;

packages/react-reconciler/src/ReactFiberReconciler.new.js

@@ -87,6 +87,7 @@ import {
   findHostInstancesForRefresh,
 } from './ReactFiberHotReloading.new';
 
+export {registerMutableSourceForHydration} from './ReactMutableSource.new';
 export {createPortal} from './ReactPortal';
 export {
   createComponentSelector,

packages/react-reconciler/src/ReactFiberReconciler.old.js

@@ -85,6 +85,7 @@ import {
   findHostInstancesForRefresh,
 } from './ReactFiberHotReloading.old';
 
+export {registerMutableSourceForHydration} from './ReactMutableSource.old';
 export {createPortal} from './ReactPortal';
 export {
   createComponentSelector,

packages/react-reconciler/src/ReactMutableSource.js

@@ -10,14 +10,6 @@ jest.mock('react-reconciler/src/ReactFiberReconciler', () => {
   );
 });
 
-jest.mock('react-reconciler/src/ReactMutableSource', () => {
-  return require.requireActual(
-    __VARIANT__
-      ? 'react-reconciler/src/ReactMutableSource.new'
-      : 'react-reconciler/src/ReactMutableSource.old'
-  );
-});
-
 // When testing the custom renderer code path through `react-reconciler`,
 // turn the export into a function, and use the argument as host config.
 const shimHostConfigPath = 'react-reconciler/src/ReactFiberHostConfig';

scripts/jest/setupHostConfigs.js

@@ -280,26 +280,6 @@ const forks = Object.freeze({
     return 'react-reconciler/src/ReactFiberReconciler.old.js';
   },
 
-  'react-reconciler/src/ReactMutableSource': (
-    bundleType,
-    entry,
-    dependencies,
-    moduleType,
-    bundle
-  ) => {
-    if (bundle.enableNewReconciler) {
-      switch (bundleType) {
-        case FB_WWW_DEV:
-        case FB_WWW_PROD:
-        case FB_WWW_PROFILING:
-          // Use the forked version of the reconciler
-          return 'react-reconciler/src/ReactMutableSource.new.js';
-      }
-    }
-    // Otherwise, use the non-forked version.
-    return 'react-reconciler/src/ReactMutableSource.old.js';
-  },
-
   'react-reconciler/src/ReactFiberHotReloading': (
     bundleType,
     entry,