Refactor: ReactInstance: Store JsErrorHandler inside a shared_ptr

Summary:
Just makes it easier to pass around JsErrorHandler.

We'll need this in D55547897, when we start storing the "has fataled" boolean inside the JsErrorHandler.

Changelog: [internal]

Reviewed By: cipolleschi

Differential Revision: D55547898

Author: RSNara

packages/react-native/ReactCommon/react/runtime/ReactInstance.cpp

@@ -36,7 +36,8 @@ ReactInstance::ReactInstance(
     : runtime_(std::move(runtime)),
       jsMessageQueueThread_(jsMessageQueueThread),
       timerManager_(std::move(timerManager)),
-      jsErrorHandler_(std::move(jsErrorHandlingFunc)),
+      jsErrorHandler_(
+          std::make_shared<JsErrorHandler>(std::move(jsErrorHandlingFunc))),
       hasFatalJsError_(std::make_shared<bool>(false)),
       parentInspectorTarget_(parentInspectorTarget) {
   RuntimeExecutor runtimeExecutor = [weakRuntime = std::weak_ptr(runtime_),
@@ -224,7 +225,7 @@ void ReactInstance::loadScript(
         } catch (jsi::JSError& error) {
           // Handle uncaught JS errors during loading JS bundle
           *hasFatalJsError_ = true;
-          this->jsErrorHandler_.handleJsError(error, true);
+          jsErrorHandler_->handleJsError(error, true);
         }
       });
 }

packages/react-native/ReactCommon/react/runtime/ReactInstance.h

@@ -80,7 +80,7 @@ class ReactInstance final : private jsinspector_modern::InstanceTargetDelegate {
   std::shared_ptr<TimerManager> timerManager_;
   std::unordered_map<std::string, std::shared_ptr<CallableModule>> modules_;
   std::shared_ptr<RuntimeScheduler> runtimeScheduler_;
-  JsErrorHandler jsErrorHandler_;
+  std::shared_ptr<JsErrorHandler> jsErrorHandler_;
 
   // Whether there are errors caught during bundle loading
   std::shared_ptr<bool> hasFatalJsError_;