Clean up class forward declaration, as follow up of cl/265533440

PiperOrigin-RevId: 285469859

Author: cynthiajiang

app/src/include/firebase/app.h

@@ -54,40 +54,6 @@ class FunctionRegistry;
 namespace internal {
 class AppInternal;
 }  // namespace internal
-namespace auth {
-class Auth;
-}  // namespace auth
-namespace crashlytics {
-namespace internal {
-class CrashlyticsInternal;
-}  // namespace internal
-}  // namespace crashlytics
-namespace database {
-namespace internal {
-class DatabaseInternal;
-}  // namespace internal
-}  // namespace database
-#ifdef INTERNAL_EXPERIMENTAL
-namespace firestore {
-class FirestoreInternal;
-}  // namespace firestore
-#endif  // INTERNAL_EXPERIMENTAL
-namespace functions {
-namespace internal {
-class FunctionsInternal;
-}  // namespace internal
-}  // namespace functions
-namespace internal {
-class InstanceId;
-}  // namespace internal
-namespace instance_id {
-class InstanceId;
-}  // namespace instance_id
-namespace storage {
-namespace internal {
-class StorageInternal;
-}  // namespace internal
-}  // namespace storage
 
 /// @brief Reports whether a Firebase module initialized successfully.
 enum InitResult {

storage/src/include/firebase/storage/listener.h

@@ -23,6 +23,7 @@ namespace storage {
 /// @cond FIREBASE_APP_INTERNAL
 namespace internal {
 class ListenerInternal;
+class StorageInternal;
 class StorageReferenceInternal;
 class RestOperation;
 }  // namespace internal

storage/src/include/firebase/storage/metadata.h

@@ -28,6 +28,7 @@ namespace storage {
 namespace internal {
 class MetadataInternal;
 class MetadataInternalCommon;
+class StorageInternal;
 class StorageReferenceInternal;
 }  // namespace internal
 

storage/src/include/firebase/storage/storage_reference.h

@@ -33,6 +33,7 @@ class Storage;
 namespace internal {
 class ControllerInternal;
 class MetadataInternal;
+class StorageInternal;
 class StorageReferenceInternalCommon;
 class StorageReferenceInternal;
 }  // namespace internal