old_contents: /**
   * Copyright (c) Facebook, Inc. and its affiliates.
   *
   * 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 'shared/invariant';
  
  import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
  import typeof * as PersistentFeatureFlagsType from './ReactFeatureFlags.persistent';
  
  export const debugRenderPhaseSideEffects = false;
  export const debugRenderPhaseSideEffectsForStrictMode = false;
  export const enableUserTimingAPI = __DEV__;
  export const enableHooks = false;
  export const warnAboutDeprecatedLifecycles = false;
  export const replayFailedUnitOfWorkWithInvokeGuardedCallback = false;
  export const enableProfilerTimer = false;
  export const enableSchedulerTracing = false;
  export const enableSuspenseServerRenderer = false;
  export const enableStableConcurrentModeAPIs = 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<PersistentFeatureFlagsType, FeatureFlagsType>);
  
new_contents: /**
   * Copyright (c) Facebook, Inc. and its affiliates.
   *
   * 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 'shared/invariant';
  
  import typeof * as FeatureFlagsType from 'shared/ReactFeatureFlags';
  import typeof * as PersistentFeatureFlagsType from './ReactFeatureFlags.persistent';
  
  export const debugRenderPhaseSideEffects = false;
  export const debugRenderPhaseSideEffectsForStrictMode = false;
  export const enableUserTimingAPI = __DEV__;
  export const enableHooks = true;
  export const warnAboutDeprecatedLifecycles = false;
  export const replayFailedUnitOfWorkWithInvokeGuardedCallback = false;
  export const enableProfilerTimer = false;
  export const enableSchedulerTracing = false;
  export const enableSuspenseServerRenderer = false;
  export const enableStableConcurrentModeAPIs = 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<PersistentFeatureFlagsType, FeatureFlagsType>);
  
subject: Enable hooks in www test renderer, too