Do not eagerly allocate all view managers in DefaultReactNativeHost (#42869)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/42869

`DefaultReactNativeHost` builds a `ViewManagerRegistry` based on a list of ViewManagers, which is inefficient, as we have to allocate them all ahead of time (defeating the purpose of `ViewManagerOnDemandReactPackage`). Instead provide a `ViewManagerResolver`which lazily resolves them.

Changelog: [Internal]

Reviewed By: cortinico

Differential Revision: D53406841

fbshipit-source-id: be8437e2127fb6741d1948cecbcf5c3d9f8de268

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/defaults/DefaultReactNativeHost.kt

@@ -11,7 +11,6 @@ import android.app.Application
 import android.content.Context
 import com.facebook.react.JSEngineResolutionAlgorithm
 import com.facebook.react.ReactHost
-import com.facebook.react.ReactInstanceManager
 import com.facebook.react.ReactNativeHost
 import com.facebook.react.ReactPackageTurboModuleManagerDelegate
 import com.facebook.react.bridge.ReactApplicationContext
@@ -20,6 +19,7 @@ import com.facebook.react.fabric.ComponentFactory
 import com.facebook.react.fabric.FabricUIManagerProviderImpl
 import com.facebook.react.fabric.ReactNativeConfig
 import com.facebook.react.uimanager.ViewManagerRegistry
+import com.facebook.react.uimanager.ViewManagerResolver
 
 /**
  * A utility class that allows you to simplify the setup of a [ReactNativeHost] for new apps in Open
@@ -46,13 +46,17 @@ protected constructor(
       if (isNewArchEnabled) {
         UIManagerProvider { reactApplicationContext: ReactApplicationContext ->
           val componentFactory = ComponentFactory()
-
           DefaultComponentsRegistry.register(componentFactory)
 
-          val reactInstanceManager: ReactInstanceManager = getReactInstanceManager()
+          val viewManagerRegistry =
+              ViewManagerRegistry(
+                  object : ViewManagerResolver {
+                    override fun getViewManager(viewManagerName: String) =
+                        reactInstanceManager.createViewManager(viewManagerName)
+
+                    override fun getViewManagerNames() = reactInstanceManager.viewManagerNames
+                  })
 
-          val viewManagers = reactInstanceManager.getOrCreateViewManagers(reactApplicationContext)
-          val viewManagerRegistry = ViewManagerRegistry(viewManagers)
           FabricUIManagerProviderImpl(
                   componentFactory, ReactNativeConfig.DEFAULT_CONFIG, viewManagerRegistry)
               .createUIManager(reactApplicationContext)