Fling: Cleanup virtualViewActivityBehavior

Summary:
Cleans up the `virtualViewActivityBehavior` feature flag, which never shipped. More work is needed if we want to use `Activity` without significantly increasing memory usage and increasing the likelihood of OOMs.

Changelog:
[Internal]

Differential Revision: D90335258

Author: yungsters

packages/react-native/scripts/featureflags/ReactNativeFeatureFlags.config.js

@@ -1063,16 +1063,6 @@ const definitions: FeatureFlagDefinitions = {
       },
       ossReleaseStage: 'none',
     },
-    virtualViewActivityBehavior: {
-      defaultValue: 'no-activity',
-      metadata: {
-        dateAdded: '2025-08-27',
-        description: 'Changes whether and how `VirtualView` uses `Activity`.',
-        expectedReleaseValue: true,
-        purpose: 'experimentation',
-      },
-      ossReleaseStage: 'none',
-    },
   },
 };
 

packages/react-native/src/private/components/virtualview/VirtualView.js

@@ -15,14 +15,12 @@ import type {NativeModeChangeEvent} from './VirtualViewNativeComponent';
 
 import UIManager from '../../../../Libraries/ReactNative/UIManager';
 import StyleSheet from '../../../../Libraries/StyleSheet/StyleSheet';
-import * as ReactNativeFeatureFlags from '../../featureflags/ReactNativeFeatureFlags';
 import {useVirtualViewLogging} from './logger/VirtualViewLogger';
 import VirtualViewExperimentalNativeComponent from './VirtualViewExperimentalNativeComponent';
 import VirtualViewProperNativeComponent from './VirtualViewNativeComponent';
 import nullthrows from 'nullthrows';
 import * as React from 'react';
-// $FlowFixMe[missing-export]
-import {startTransition, unstable_Activity as Activity, useState} from 'react';
+import {startTransition, useState} from 'react';
 
 // @see VirtualViewNativeComponent
 export enum VirtualViewMode {
@@ -155,17 +153,7 @@ function createVirtualView(initialState: State): VirtualViewComponent {
             : style
         }
         onModeChange={handleModeChange}>
-        {
-          match (ReactNativeFeatureFlags.virtualViewActivityBehavior()) {
-            'activity-without-mode' =>
-              <Activity>{isHidden ? null : children}</Activity>,
-            'activity-with-hidden-mode' =>
-              <Activity mode={isHidden ? 'hidden' : 'visible'}>
-                {children}
-              </Activity>,
-            'no-activity' | _ => isHidden ? null : children,
-          }
-        }
+        {isHidden ? null : children}
       </VirtualViewNativeComponent>
     );
   }

packages/react-native/src/private/featureflags/ReactNativeFeatureFlags.js

@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<480e58e52425586928349b9f3560ce7f>>
+ * @generated SignedSource<<fcf8bc19a86d7c5ffc3b36c01348df26>>
  * @flow strict
  * @noformat
  */
@@ -41,7 +41,6 @@ export type ReactNativeFeatureFlagsJsOnly = $ReadOnly<{
   shouldUseLinkRoleForPressableText: Getter<boolean>,
   shouldUseRemoveClippedSubviewsAsDefaultOnIOS: Getter<boolean>,
   shouldUseSetNativePropsInFabric: Getter<boolean>,
-  virtualViewActivityBehavior: Getter<string>,
 }>;
 
 export type ReactNativeFeatureFlagsJsOnlyOverrides = OverridesFor<ReactNativeFeatureFlagsJsOnly>;
@@ -199,11 +198,6 @@ export const shouldUseRemoveClippedSubviewsAsDefaultOnIOS: Getter<boolean> = cre
  */
 export const shouldUseSetNativePropsInFabric: Getter<boolean> = createJavaScriptFlagGetter('shouldUseSetNativePropsInFabric', true);
 
-/**
- * Changes whether and how `VirtualView` uses `Activity`.
- */
-export const virtualViewActivityBehavior: Getter<string> = createJavaScriptFlagGetter('virtualViewActivityBehavior', "no-activity");
-
 /**
  * Common flag for testing. Do NOT modify.
  */