Fix initialization of Facebook/Twitter Utils blocking the main thread.

Parse/Internal/PFCoreManager.m

@@ -305,7 +305,7 @@ - (PFUserAuthenticationController *)userAuthenticationController {
     __block PFUserAuthenticationController *controller = nil;
     dispatch_sync(_controllerAccessQueue, ^{
         if (!_userAuthenticationController) {
-            _userAuthenticationController = [[PFUserAuthenticationController alloc] init];
+            _userAuthenticationController = [PFUserAuthenticationController controllerWithDataSource:self];
         }
         controller = _userAuthenticationController;
     });

Parse/Internal/User/AuthenticationProviders/Controller/PFUserAuthenticationController.h

@@ -12,13 +12,27 @@
 #import <Parse/PFConstants.h>
 #import <Parse/PFUserAuthenticationDelegate.h>
 
+#import "PFCoreDataProvider.h"
+
 NS_ASSUME_NONNULL_BEGIN
 
 @class BFTask PF_GENERIC(__covariant BFGenericType);
 @class PFUser;
 
 @interface PFUserAuthenticationController : NSObject
 
+@property (nonatomic, weak, readonly) id<PFCurrentUserControllerProvider> dataSource;
+
+///--------------------------------------
+/// @name Init
+///--------------------------------------
+
+- (instancetype)init NS_UNAVAILABLE;
++ (instancetype)new NS_UNAVAILABLE;
+
+- (instancetype)initWithDataSource:(id<PFCurrentUserControllerProvider>)dataSource;
++ (instancetype)controllerWithDataSource:(id<PFCurrentUserControllerProvider>)dataSource;
+
 ///--------------------------------------
 /// @name Authentication Providers
 ///--------------------------------------

Parse/Internal/User/AuthenticationProviders/Controller/PFUserAuthenticationController.m

@@ -16,6 +16,7 @@
 #import "PFAnonymousUtils.h"
 #import "PFAnonymousAuthenticationProvider.h"
 #import "PFUserController.h"
+#import "PFCurrentUserController.h"
 #import "PFAssert.h"
 
 @interface PFUserAuthenticationController () {
@@ -31,16 +32,21 @@ @implementation PFUserAuthenticationController
 #pragma mark - Init
 ///--------------------------------------
 
-- (instancetype)init {
+- (instancetype)initWithDataSource:(id<PFCurrentUserControllerProvider>)dataSource {
     self = [super init];
     if (!self) return nil;
 
+    _dataSource = dataSource;
     _dataAccessQueue = dispatch_queue_create("com.parse.user.authenticationManager", DISPATCH_QUEUE_SERIAL);
     _authenticationDelegates = [NSMutableDictionary dictionary];
 
     return self;
 }
 
++ (instancetype)controllerWithDataSource:(id<PFCurrentUserControllerProvider>)dataSource {
+    return [[self alloc] initWithDataSource:dataSource];
+}
+
 ///--------------------------------------
 #pragma mark - Authentication Providers
 ///--------------------------------------
@@ -56,9 +62,11 @@ - (void)registerAuthenticationDelegate:(id<PFUserAuthenticationDelegate>)delegat
     });
 
     // TODO: (nlutsenko) Decouple this further.
-    if (![authType isEqualToString:PFAnonymousUserAuthenticationType]) {
-        [[PFUser currentUser] synchronizeAuthDataWithAuthType:authType];
-    }
+    [[self.dataSource.currentUserController getCurrentUserAsyncWithOptions:0] continueWithSuccessBlock:^id(BFTask *task) {
+        PFUser *user = task.result;
+        [user synchronizeAuthDataWithAuthType:authType];
+        return nil;
+    }];
 }
 
 - (void)unregisterAuthenticationDelegateForAuthType:(NSString *)authType {