Split editor entity activation from PrefabSystemComponent (#6787)

* Split editor entity activation from PrefabSystemComponent

Signed-off-by: srikappa-amzn <82230713+srikappa-amzn@users.noreply.github.com>

* Fixed a small typo

Signed-off-by: srikappa-amzn <82230713+srikappa-amzn@users.noreply.github.com>

* Pass entity activation callback during prefab instantiation for failing tests

Signed-off-by: srikappa-amzn <82230713+srikappa-amzn@users.noreply.github.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.cpp

@@ -277,7 +277,7 @@ namespace AzToolsFramework
         }
 
         AZStd::unique_ptr<Instance> PrefabSystemComponent::InstantiatePrefab(
-            AZ::IO::PathView filePath, InstanceOptionalReference parent)
+            AZ::IO::PathView filePath, InstanceOptionalReference parent, const InstantiatedEntitiesCallback& instantiatedEntitiesCallback)
         {
             // Retrieve the template id for the source prefab filepath
             Prefab::TemplateId templateId = GetTemplateIdFromFilePath(filePath);
@@ -297,11 +297,11 @@ namespace AzToolsFramework
                 return nullptr;
             }
 
-            return InstantiatePrefab(templateId, parent);
+            return InstantiatePrefab(templateId, parent, instantiatedEntitiesCallback);
         }
 
         AZStd::unique_ptr<Instance> PrefabSystemComponent::InstantiatePrefab(
-            TemplateId templateId, InstanceOptionalReference parent)
+            TemplateId templateId, InstanceOptionalReference parent, const InstantiatedEntitiesCallback& instantiatedEntitiesCallback)
         {
             TemplateReference instantiatingTemplate = FindTemplate(templateId);
 
@@ -324,8 +324,10 @@ namespace AzToolsFramework
                 return nullptr;
             }
 
-            AzToolsFramework::EditorEntityContextRequestBus::Broadcast(
-                &AzToolsFramework::EditorEntityContextRequests::HandleEntitiesAdded, newEntities);
+            if (instantiatedEntitiesCallback)
+            {
+                instantiatedEntitiesCallback(newEntities);
+            }
 
             return newInstance;
         }

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponent.h

@@ -124,19 +124,25 @@ namespace AzToolsFramework
             * Generates a new Prefab Instance based on the Template whose source is stored in filepath.
             * @param filePath The path to the prefab source file containing the template being instantiated.
             * @param parent Reference of the target instance the instantiated instance will be placed under.
+            * @param instantiatedEntitiesCallback An optional callback that can be used to modify the instantiated entities.
             * @return A unique_ptr to the newly instantiated instance. Null if operation failed.
             */
             AZStd::unique_ptr<Instance> InstantiatePrefab(
-                AZ::IO::PathView filePath, InstanceOptionalReference parent = AZStd::nullopt) override;
+                AZ::IO::PathView filePath,
+                InstanceOptionalReference parent = AZStd::nullopt,
+                const InstantiatedEntitiesCallback& instantiatedEntitiesCallback = {}) override;
 
             /**
             * Generates a new Prefab Instance based on the Template referenced by templateId.
             * @param templateId The id of the template being instantiated.
             * @param parent Reference of the target instance the instantiated instance will be placed under.
+            * @param instantiatedEntitiesCallback An optional callback that can be used to modify the instantiated entities.
             * @return A unique_ptr to the newly instantiated instance. Null if operation failed.
             */
             AZStd::unique_ptr<Instance> InstantiatePrefab(
-                TemplateId templateId, InstanceOptionalReference parent = AZStd::nullopt) override;
+                TemplateId templateId,
+                InstanceOptionalReference parent = AZStd::nullopt,
+                const InstantiatedEntitiesCallback& instantiatedEntitiesCallback = {}) override;
 
             /**
             * Add a new Link into Prefab System Component and create a unique id for it.

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabSystemComponentInterface.h

@@ -27,6 +27,9 @@ namespace AzToolsFramework
         class PrefabSystemComponentInterface
         {
         public:
+
+            using InstantiatedEntitiesCallback = AZStd::function<void(AZStd::vector<AZ::Entity*>&)>;
+
             AZ_RTTI(PrefabSystemComponentInterface, "{8E95A029-67F9-4F74-895F-DDBFE29516A0}");
 
             virtual TemplateReference FindTemplate(TemplateId id) = 0;
@@ -70,9 +73,13 @@ namespace AzToolsFramework
             virtual void PropagateTemplateChanges(TemplateId templateId, InstanceOptionalConstReference instanceToExclude = AZStd::nullopt) = 0;
 
             virtual AZStd::unique_ptr<Instance> InstantiatePrefab(
-                AZ::IO::PathView filePath, InstanceOptionalReference parent = AZStd::nullopt) = 0;
+                AZ::IO::PathView filePath,
+                InstanceOptionalReference parent = AZStd::nullopt,
+                const InstantiatedEntitiesCallback& instantiatedEntitiesCallback = {}) = 0;
             virtual AZStd::unique_ptr<Instance> InstantiatePrefab(
-                TemplateId templateId, InstanceOptionalReference parent = AZStd::nullopt) = 0;
+                TemplateId templateId,
+                InstanceOptionalReference parent = AZStd::nullopt,
+                const InstantiatedEntitiesCallback& instantiatedEntitiesCallback = {}) = 0;
             virtual AZStd::unique_ptr<Instance> CreatePrefab(const AZStd::vector<AZ::Entity*>& entities,
                 AZStd::vector<AZStd::unique_ptr<Instance>>&& instancesToConsume, AZ::IO::PathView filePath,
                 AZStd::unique_ptr<AZ::Entity> containerEntity = nullptr, InstanceOptionalReference parent = AZStd::nullopt,