Introduce fuseboxFrameRecordingEnabled flag, gate existing code (react#55941)

Summary:
Pull Request resolved: react#55941

Replaces the previous `globalThis.enableTimelineFrames` setup with backend gating.

Enables us to:
- Iterate more safely by gating Android/iOS/C++ code
- Have a per-app rollout at Meta

Changelog: [Internal]

Reviewed By: vzaidman

Differential Revision: D95405444

fbshipit-source-id: 0c41f10059b28ed940a12a44707946baa310bdfb

Author: huntie

.claude/settings.local.json

@@ -1,7 +1,12 @@
 {
   "permissions": {
     "allow": [
-      "Bash(gh log-list:*)"
+      "Bash(gh log-list:*)",
+      "Bash(for f:*)",
+      "Bash(do)",
+      "Bash(echo \"=== $f ===\")",
+      "Read(//Users/huntie/Development/forks/facebook/react-native/**)",
+      "Bash(done)"
     ]
   }
 }

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/devsupport/InspectorFlags.kt

@@ -20,4 +20,6 @@ internal object InspectorFlags {
   @DoNotStrip @JvmStatic external fun getFuseboxEnabled(): Boolean
 
   @DoNotStrip @JvmStatic external fun getIsProfilingBuild(): Boolean
+
+  @DoNotStrip @JvmStatic external fun getFrameRecordingEnabled(): Boolean
 }

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlags.kt

@@ -372,6 +372,12 @@ public object ReactNativeFeatureFlags {
   @JvmStatic
   public fun fuseboxEnabledRelease(): Boolean = accessor.fuseboxEnabledRelease()
 
+  /**
+   * Enable frame timings and screenshots support in the React Native DevTools CDP backend. This flag is global and should not be changed across React Host lifetimes.
+   */
+  @JvmStatic
+  public fun fuseboxFrameRecordingEnabled(): Boolean = accessor.fuseboxFrameRecordingEnabled()
+
   /**
    * Enable network inspection support in the React Native DevTools CDP backend. Requires `enableBridgelessArchitecture`. This flag is global and should not be changed across React Host lifetimes.
    */

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxAccessor.kt

@@ -77,6 +77,7 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
   private var fixMappingOfEventPrioritiesBetweenFabricAndReactCache: Boolean? = null
   private var fuseboxAssertSingleHostStateCache: Boolean? = null
   private var fuseboxEnabledReleaseCache: Boolean? = null
+  private var fuseboxFrameRecordingEnabledCache: Boolean? = null
   private var fuseboxNetworkInspectionEnabledCache: Boolean? = null
   private var hideOffscreenVirtualViewsOnIOSCache: Boolean? = null
   private var overrideBySynchronousMountPropsAtMountingAndroidCache: Boolean? = null
@@ -619,6 +620,15 @@ internal class ReactNativeFeatureFlagsCxxAccessor : ReactNativeFeatureFlagsAcces
     return cached
   }
 
+  override fun fuseboxFrameRecordingEnabled(): Boolean {
+    var cached = fuseboxFrameRecordingEnabledCache
+    if (cached == null) {
+      cached = ReactNativeFeatureFlagsCxxInterop.fuseboxFrameRecordingEnabled()
+      fuseboxFrameRecordingEnabledCache = cached
+    }
+    return cached
+  }
+
   override fun fuseboxNetworkInspectionEnabled(): Boolean {
     var cached = fuseboxNetworkInspectionEnabledCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsCxxInterop.kt

@@ -142,6 +142,8 @@ public object ReactNativeFeatureFlagsCxxInterop {
 
   @DoNotStrip @JvmStatic public external fun fuseboxEnabledRelease(): Boolean
 
+  @DoNotStrip @JvmStatic public external fun fuseboxFrameRecordingEnabled(): Boolean
+
   @DoNotStrip @JvmStatic public external fun fuseboxNetworkInspectionEnabled(): Boolean
 
   @DoNotStrip @JvmStatic public external fun hideOffscreenVirtualViewsOnIOS(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsDefaults.kt

@@ -137,6 +137,8 @@ public open class ReactNativeFeatureFlagsDefaults : ReactNativeFeatureFlagsProvi
 
   override fun fuseboxEnabledRelease(): Boolean = false
 
+  override fun fuseboxFrameRecordingEnabled(): Boolean = false
+
   override fun fuseboxNetworkInspectionEnabled(): Boolean = true
 
   override fun hideOffscreenVirtualViewsOnIOS(): Boolean = false

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsLocalAccessor.kt

@@ -81,6 +81,7 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
   private var fixMappingOfEventPrioritiesBetweenFabricAndReactCache: Boolean? = null
   private var fuseboxAssertSingleHostStateCache: Boolean? = null
   private var fuseboxEnabledReleaseCache: Boolean? = null
+  private var fuseboxFrameRecordingEnabledCache: Boolean? = null
   private var fuseboxNetworkInspectionEnabledCache: Boolean? = null
   private var hideOffscreenVirtualViewsOnIOSCache: Boolean? = null
   private var overrideBySynchronousMountPropsAtMountingAndroidCache: Boolean? = null
@@ -680,6 +681,16 @@ internal class ReactNativeFeatureFlagsLocalAccessor : ReactNativeFeatureFlagsAcc
     return cached
   }
 
+  override fun fuseboxFrameRecordingEnabled(): Boolean {
+    var cached = fuseboxFrameRecordingEnabledCache
+    if (cached == null) {
+      cached = currentProvider.fuseboxFrameRecordingEnabled()
+      accessedFeatureFlags.add("fuseboxFrameRecordingEnabled")
+      fuseboxFrameRecordingEnabledCache = cached
+    }
+    return cached
+  }
+
   override fun fuseboxNetworkInspectionEnabled(): Boolean {
     var cached = fuseboxNetworkInspectionEnabledCache
     if (cached == null) {

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/internal/featureflags/ReactNativeFeatureFlagsProvider.kt

@@ -137,6 +137,8 @@ public interface ReactNativeFeatureFlagsProvider {
 
   @DoNotStrip public fun fuseboxEnabledRelease(): Boolean
 
+  @DoNotStrip public fun fuseboxFrameRecordingEnabled(): Boolean
+
   @DoNotStrip public fun fuseboxNetworkInspectionEnabled(): Boolean
 
   @DoNotStrip public fun hideOffscreenVirtualViewsOnIOS(): Boolean

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/runtime/ReactHostImpl.kt

@@ -1573,16 +1573,18 @@ public class ReactHostImpl(
           when (state) {
             TracingState.ENABLED_IN_BACKGROUND_MODE,
             TracingState.ENABLED_IN_CDP_MODE -> {
-              val observer =
-                  FrameTimingsObserver(
-                      _screenshotsEnabled,
-                      { frameTimingsSequence ->
-                        inspectorTarget.recordFrameTimings(frameTimingsSequence)
-                      },
-                  )
-              observer.setCurrentWindow(currentActivity?.window)
-              observer.start()
-              frameTimingsObserver = observer
+              if (InspectorFlags.getFrameRecordingEnabled()) {
+                val observer =
+                    FrameTimingsObserver(
+                        _screenshotsEnabled,
+                        { frameTimingsSequence ->
+                          inspectorTarget.recordFrameTimings(frameTimingsSequence)
+                        },
+                    )
+                observer.setCurrentWindow(currentActivity?.window)
+                observer.start()
+                frameTimingsObserver = observer
+              }
             }
             TracingState.DISABLED -> {
               frameTimingsObserver?.stop()

packages/react-native/ReactAndroid/src/main/jni/react/devsupport/JInspectorFlags.cpp

@@ -21,6 +21,12 @@ bool JInspectorFlags::getIsProfilingBuild(jni::alias_ref<jclass> /*unused*/) {
   return inspectorFlags.getIsProfilingBuild();
 }
 
+bool JInspectorFlags::getFrameRecordingEnabled(
+    jni::alias_ref<jclass> /*unused*/) {
+  auto& inspectorFlags = InspectorFlags::getInstance();
+  return inspectorFlags.getFrameRecordingEnabled();
+}
+
 void JInspectorFlags::registerNatives() {
   javaClassLocal()->registerNatives({
       makeNativeMethod("getFuseboxEnabled", JInspectorFlags::getFuseboxEnabled),
@@ -29,6 +35,11 @@ void JInspectorFlags::registerNatives() {
       makeNativeMethod(
           "getIsProfilingBuild", JInspectorFlags::getIsProfilingBuild),
   });
+  javaClassLocal()->registerNatives({
+      makeNativeMethod(
+          "getFrameRecordingEnabled",
+          JInspectorFlags::getFrameRecordingEnabled),
+  });
 }
 
 } // namespace facebook::react::jsinspector_modern