Add static injection for feature flags (#11269)

* Replace ReactDOMFeatureFlags with ReactFeatureFlags

* Add static injection for feature flags

scripts/rollup/build.js

@@ -372,7 +372,8 @@ function getPlugins(
   hasteName,
   moduleType,
   manglePropertiesOnProd,
-  modulesToStub
+  modulesToStub,
+  featureFlags
 ) {
   const plugins = [
     babel(updateBabelConfig(babelOpts, bundleType)),
@@ -383,7 +384,8 @@ function getPlugins(
 
   const replaceModules = Modules.getDefaultReplaceModules(
     bundleType,
-    modulesToStub
+    modulesToStub,
+    featureFlags
   );
 
   // We have to do this check because Rollup breaks on empty object.
@@ -525,7 +527,8 @@ function createBundle(bundle, bundleType) {
       bundle.hasteName,
       bundle.moduleType,
       bundle.manglePropertiesOnProd,
-      bundle.modulesToStub
+      bundle.modulesToStub,
+      bundle.featureFlags
     ),
   })
     .then(result =>

scripts/rollup/modules.js

@@ -124,7 +124,6 @@ function ignoreFBModules() {
   return [
     // At FB, we don't know them statically:
     'ReactFeatureFlags',
-    'ReactDOMFeatureFlags',
     // In FB bundles, we preserve an inline require to ReactCurrentOwner.
     // See the explanation in FB version of ReactCurrentOwner in www:
     'ReactCurrentOwner',
@@ -297,13 +296,27 @@ function getAliases(paths, bundleType, moduleType, extractErrors) {
   );
 }
 
-function getDefaultReplaceModules(bundleType, bundleModulesToStub) {
+function replaceFeatureFlags(featureFlags) {
+  if (!featureFlags) {
+    return {};
+  }
+  return {
+    "'ReactFeatureFlags'": `'${resolve(featureFlags)}'`,
+  };
+}
+
+function getDefaultReplaceModules(
+  bundleType,
+  bundleModulesToStub,
+  featureFlags
+) {
   return Object.assign(
     {},
     replaceFbjsModuleAliases(bundleType),
     replaceDevOnlyStubbedModules(bundleType),
     replaceLegacyModuleAliases(bundleType),
-    replaceBundleStubModules(bundleModulesToStub)
+    replaceBundleStubModules(bundleModulesToStub),
+    replaceFeatureFlags(featureFlags)
   );
 }
 

src/renderers/dom/fiber/ReactDOMFiberEntry.js

@@ -17,8 +17,8 @@ var DOMNamespaces = require('DOMNamespaces');
 var ExecutionEnvironment = require('fbjs/lib/ExecutionEnvironment');
 var ReactBrowserEventEmitter = require('ReactBrowserEventEmitter');
 var ReactControlledComponent = require('ReactControlledComponent');
+var ReactFeatureFlags = require('ReactFeatureFlags');
 var ReactDOMComponentTree = require('ReactDOMComponentTree');
-var ReactDOMFeatureFlags = require('ReactDOMFeatureFlags');
 var ReactDOMFiberComponent = require('ReactDOMFiberComponent');
 var ReactDOMFrameScheduling = require('ReactDOMFrameScheduling');
 var ReactGenericBatching = require('ReactGenericBatching');
@@ -632,7 +632,7 @@ var DOMRenderer = ReactFiberReconciler({
 
   scheduleDeferredCallback: ReactDOMFrameScheduling.rIC,
 
-  useSyncScheduling: !ReactDOMFeatureFlags.fiberAsyncScheduling,
+  useSyncScheduling: !ReactFeatureFlags.enableAsyncSchedulingByDefaultInReactDOM,
 });
 
 ReactGenericBatching.injection.injectFiberBatchedUpdates(

src/renderers/dom/shared/ReactDOMFeatureFlags.js

@@ -1,16 +0,0 @@
-/**
- * Copyright (c) 2013-present, Facebook, Inc.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- *
- * @providesModule ReactDOMFeatureFlags
- */
-
-'use strict';
-
-var ReactDOMFeatureFlags = {
-  fiberAsyncScheduling: false,
-};
-
-module.exports = ReactDOMFeatureFlags;

src/renderers/shared/utils/ReactFeatureFlags.js

@@ -10,8 +10,20 @@
 
 'use strict';
 
-var ReactFeatureFlags = {
+export type FeatureFlags = {|
+  enableAsyncSubtreeAPI: boolean,
+  enableAsyncSchedulingByDefaultInReactDOM: boolean,
+|};
+
+var ReactFeatureFlags: FeatureFlags = {
   enableAsyncSubtreeAPI: true,
+  enableAsyncSchedulingByDefaultInReactDOM: false,
 };
 
+if (__DEV__) {
+  if (Object.freeze) {
+    Object.freeze(ReactFeatureFlags);
+  }
+}
+
 module.exports = ReactFeatureFlags;