Gate early EventEmitter update during PreAllocation behind feature flag

Summary:
This feature is still causing some number of crashes, though prod impact is not yet determined. For safety I'm adding a feature flag so we can disable this if necessary.

Changelog: [internal]

Reviewed By: kacieb

Differential Revision: D29117957

fbshipit-source-id: 3b19bac9dd00735f51f5c9cba606378b2a62975e

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.cpp

@@ -564,6 +564,9 @@ void Binding::installFabricUIManager(
   disableVirtualNodePreallocation_ = reactNativeConfig_->getBool(
       "react_fabric:disable_virtual_node_preallocation");
 
+  enableEarlyEventEmitterUpdate_ = reactNativeConfig_->getBool(
+      "react_fabric:enable_early_event_emitter_update");
+
   auto toolbox = SchedulerToolbox{};
   toolbox.contextContainer = contextContainer;
   toolbox.componentRegistryFactory = componentsRegistry->buildRegistryFunction;
@@ -1162,10 +1165,12 @@ void Binding::preallocateShadowView(
   }
 
   // Do not hold a reference to javaEventEmitter from the C++ side.
-  SharedEventEmitter eventEmitter = shadowView.eventEmitter;
   auto javaEventEmitter = EventEmitterWrapper::newObjectJavaArgs();
-  EventEmitterWrapper *cEventEmitter = cthis(javaEventEmitter);
-  cEventEmitter->eventEmitter = eventEmitter;
+  if (enableEarlyEventEmitterUpdate_) {
+    SharedEventEmitter eventEmitter = shadowView.eventEmitter;
+    EventEmitterWrapper *cEventEmitter = cthis(javaEventEmitter);
+    cEventEmitter->eventEmitter = eventEmitter;
+  }
 
   local_ref<ReadableMap::javaobject> props = castReadableMap(
       ReadableNativeMap::newObjectCxxArgs(shadowView.props->rawProps));

ReactAndroid/src/main/java/com/facebook/react/fabric/jni/Binding.h

@@ -194,6 +194,7 @@ class Binding : public jni::HybridClass<Binding>,
   bool disablePreallocateViews_{false};
   bool disableVirtualNodePreallocation_{false};
   bool enableFabricLogs_{false};
+  bool enableEarlyEventEmitterUpdate_{false};
 };
 
 } // namespace react