[DevTools] Disable Activity slices by default (#35685)

Author: eps1lon

packages/react-devtools-shared/src/config/DevToolsFeatureFlags.core-fb.js

@@ -13,6 +13,7 @@
  * It should always be imported from "react-devtools-feature-flags".
  ************************************************************************/
 
+export const enableActivitySlices: boolean = false;
 export const enableLogger: boolean = true;
 export const enableStyleXFeatures: boolean = true;
 export const isInternalFacebookBuild: boolean = true;

packages/react-devtools-shared/src/config/DevToolsFeatureFlags.core-oss.js

@@ -13,6 +13,7 @@
  * It should always be imported from "react-devtools-feature-flags".
  ************************************************************************/
 
+export const enableActivitySlices: boolean = __DEV__;
 export const enableLogger: boolean = false;
 export const enableStyleXFeatures: boolean = false;
 export const isInternalFacebookBuild: boolean = false;

packages/react-devtools-shared/src/config/DevToolsFeatureFlags.default.js

@@ -13,6 +13,7 @@
  * It should always be imported from "react-devtools-feature-flags".
  ************************************************************************/
 
+export const enableActivitySlices: boolean = __DEV__;
 export const enableLogger: boolean = false;
 export const enableStyleXFeatures: boolean = false;
 export const isInternalFacebookBuild: boolean = false;

packages/react-devtools-shared/src/config/DevToolsFeatureFlags.extension-fb.js

@@ -13,6 +13,7 @@
  * It should always be imported from "react-devtools-feature-flags".
  ************************************************************************/
 
+export const enableActivitySlices: boolean = false;
 export const enableLogger: boolean = true;
 export const enableStyleXFeatures: boolean = true;
 export const isInternalFacebookBuild: boolean = true;

packages/react-devtools-shared/src/config/DevToolsFeatureFlags.extension-oss.js

@@ -13,6 +13,7 @@
  * It should always be imported from "react-devtools-feature-flags".
  ************************************************************************/
 
+export const enableActivitySlices: boolean = __DEV__;
 export const enableLogger: boolean = false;
 export const enableStyleXFeatures: boolean = false;
 export const isInternalFacebookBuild: boolean = false;

packages/react-devtools-shared/src/devtools/views/SuspenseTab/SuspenseTab.js

@@ -16,6 +16,7 @@ import {
   Fragment,
 } from 'react';
 
+import {enableActivitySlices} from 'react-devtools-feature-flags';
 import {
   localStorageGetItem,
   localStorageSetItem,
@@ -284,7 +285,7 @@ function SuspenseTab(_: {}) {
   const {activities} = useContext(TreeStateContext);
   // If there are no named Activity boundaries, we don't have any tree list and we should hide
   // both the panel and the button to toggle it.
-  const activityListDisabled = activities.length === 0;
+  const activityListDisabled = !enableActivitySlices || activities.length === 0;
 
   const wrapperTreeRef = useRef<null | HTMLElement>(null);
   const resizeTreeRef = useRef<null | HTMLElement>(null);