Report Redbox error when a component is not implemented

Summary:
This diff ensures that a redbox is reported when a component is not registered in Fabric.

Changelog:
Ensure a redbox is reported when components are not registered in Fabric.

Reviewed By: shergin

Differential Revision: D17970793

fbshipit-source-id: 7afd7e6b0b9c0ff6d2bd475dbf6979d83fec093c

ReactCommon/fabric/uimanager/ComponentDescriptorRegistry.cpp

@@ -130,7 +130,13 @@ ComponentDescriptor const &ComponentDescriptorRegistry::at(
 
   auto it = _registryByName.find(unifiedComponentName);
   if (it == _registryByName.end()) {
-    assert(providerRegistry_);
+    // TODO: T54849676 Refactor this condition when RN Fabric Android starts
+    // using ComponentDescriptorProviderRegistry class
+    if (!providerRegistry_) {
+      throw std::invalid_argument(
+          ("Unable to find componentDescriptor for " + unifiedComponentName)
+              .c_str());
+    }
 
     mutex_.unlock_shared();
     providerRegistry_->request(unifiedComponentName.c_str());