Read debugRenderPhaseSideEffects from GK (facebook#11603)

* Forked ReactFeatureFlags for React Native to enable debugRenderPhaseSideEffects GK
* Changed debugRenderPhaseSideEffects in www feature flags to be runtime as well

packages/react-native-renderer/src/ReactNativeFeatureFlags.js

@@ -0,0 +1,37 @@
+/**
+ * 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.
+ *
+ * @flow
+ */
+
+import invariant from 'fbjs/lib/invariant';
+
+import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
+import typeof * as FeatureFlagsShimType from './ReactNativeFeatureFlags';
+
+// Re-export dynamic flags from the fbsource version.
+export const {debugRenderPhaseSideEffects} = require('ReactFeatureFlags');
+
+// The rest of the flags are static for better dead code elimination.
+export const enableAsyncSubtreeAPI = true;
+export const enableAsyncSchedulingByDefaultInReactDOM = false;
+export const enableReactFragment = false;
+export const enableCreateRoot = false;
+export const enableUserTimingAPI = __DEV__;
+export const enableMutatingReconciler = true;
+export const enableNoopReconciler = false;
+export const enablePersistentReconciler = false;
+
+// Only used in www builds.
+export function addUserTimingListener() {
+  invariant(false, 'Not implemented.');
+}
+
+// Flow magic to verify the exports of this file match the original version.
+// eslint-disable-next-line no-unused-vars
+type Check<_X, Y: _X, X: Y = _X> = null;
+// eslint-disable-next-line no-unused-expressions
+(null: Check<FeatureFlagsShimType, FeatureFlagsType>);

scripts/rollup/bundles.js

@@ -129,6 +129,7 @@ const bundles = [
       'deepFreezeAndThrowOnMutationInDev',
       'flattenStyle',
     ],
+    featureFlags: 'react-native-renderer/src/ReactNativeFeatureFlags',
   },
 
   /******* React Native RT *******/

scripts/rollup/shims/rollup/ReactFeatureFlags-www.js

@@ -12,11 +12,11 @@ import typeof * as FeatureFlagsShimType from './ReactFeatureFlags-www';
 
 // Re-export dynamic flags from the www version.
 export const {
+  debugRenderPhaseSideEffects,
   enableAsyncSchedulingByDefaultInReactDOM,
 } = require('ReactFeatureFlags');
 
 // The rest of the flags are static for better dead code elimination.
-export const debugRenderPhaseSideEffects = false;
 export const enableAsyncSubtreeAPI = true;
 export const enableReactFragment = false;
 export const enableCreateRoot = true;