From 7eb4de50b38c7fdf9ed0d3780987619a81007f0d Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Mon, 26 Jul 2021 15:42:21 -0700
Subject: [PATCH 1/7] Add support for Facebook Limited Login.

---
 .../Sources/FUIFacebookAuth.m                 | 142 ++++++++++++++----
 .../FirebaseFacebookAuthUI/FUIFacebookAuth.h  |   5 +
 2 files changed, 121 insertions(+), 26 deletions(-)

diff --git a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
index d34548007ad..a725edf7a1f 100644
--- a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
+++ b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
@@ -20,11 +20,13 @@
 #import <FirebaseAuth/FirebaseAuth.h>
 
 #if SWIFT_PACKAGE
+@import CommonCrypto;
 @import FBSDKCoreKit;
 @import FBSDKLoginKit;
 #else
 #import <FBSDKCoreKit/FBSDKCoreKit.h>
 #import <FBSDKLoginKit/FBSDKLoginKit.h>
+#import <CommonCrypto/CommonCrypto.h>
 #endif // SWIFT_PACKAGE
 
 /** @var kTableName
@@ -86,6 +88,11 @@ @implementation FUIFacebookAuth {
       @brief The email address associated with this account.
    */
   NSString *_email;
+
+  /** @var _currentNonce
+      @brief The current nonce for a Facebook Limited Login sign-in attempt.
+   */
+  NSString *_currentNonce;
 }
 
 + (NSBundle *)bundle {
@@ -191,29 +198,59 @@ - (void)signInWithDefaultValue:(nullable NSString *)defaultValue
     return;
   }
 
-  [_loginManager logInWithPermissions:_scopes
-                   fromViewController:presentingViewController
-                              handler:^(FBSDKLoginManagerLoginResult *result,
-                                        NSError *error) {
-    if (error) {
-      NSError *newError =
-          [FUIAuthErrorUtils providerErrorWithUnderlyingError:error
-                                                     providerID:FIRFacebookAuthProviderID];
-      [self completeSignInFlowWithAccessToken:nil error:newError];
-    } else if (result.isCancelled) {
-      NSError *newError = [FUIAuthErrorUtils userCancelledSignInError];
-      [self completeSignInFlowWithAccessToken:nil error:newError];
-    } else {
-      // Retrieve email.
-      [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me" parameters:@{ @"fields" : @"email" }] startWithCompletion:^(id<FBSDKGraphRequestConnecting> connection,
-                                id result,
-                                NSError *error) {
-        self->_email = result[@"email"];
-      }];
-      [self completeSignInFlowWithAccessToken:result.token.tokenString
-                                        error:nil];
-    }
-  }];
+  if (self.useLimitedLogin) {
+    // Facebook Limited Login
+    NSString *nonce = [self randomNonce];
+    self->_currentNonce = nonce;
+    FBSDKLoginConfiguration *configuration =
+      [[FBSDKLoginConfiguration alloc] initWithPermissions:_scopes
+                                                  tracking:FBSDKLoginTrackingLimited
+                                                     nonce:[self stringBySha256HashingString:nonce]];
+    [_loginManager logInFromViewController:presentingViewController
+                            configuration:configuration
+                               completion:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
+      if (error) {
+        NSError *newError =
+            [FUIAuthErrorUtils providerErrorWithUnderlyingError:error
+                                                       providerID:FIRFacebookAuthProviderID];
+        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
+      } else if (result.isCancelled) {
+        NSError *newError = [FUIAuthErrorUtils userCancelledSignInError];
+        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
+      } else {
+        self->_email = FBSDKProfile.currentProfile.email;
+        NSString *idToken = FBSDKAuthenticationToken.currentAuthenticationToken.tokenString;
+        [self completeSignInFlowWithAccessToken:nil idToken:idToken error:nil];
+      }
+    }];
+  } else {
+    [_loginManager logInWithPermissions:_scopes
+                     fromViewController:presentingViewController
+                                handler:^(FBSDKLoginManagerLoginResult *result,
+                                          NSError *error) {
+      if (error) {
+        NSError *newError =
+        [FUIAuthErrorUtils providerErrorWithUnderlyingError:error
+                                                 providerID:FIRFacebookAuthProviderID];
+        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
+      } else if (result.isCancelled) {
+        NSError *newError = [FUIAuthErrorUtils userCancelledSignInError];
+        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
+      } else {
+        // Retrieve email.
+        [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me"
+                                           parameters:@{ @"fields" : @"email" }]
+                                  startWithCompletion:^(id<FBSDKGraphRequestConnecting> connection,
+                                                        id result,
+                                                        NSError *error) {
+          self->_email = result[@"email"];
+        }];
+        [self completeSignInFlowWithAccessToken:result.token.tokenString
+                                        idToken:nil
+                                          error:nil];
+      }
+    }];
+  }
 }
 
 - (void)signInWithOAuthProvider:(FIROAuthProvider *)oauthProvider
@@ -272,18 +309,28 @@ - (BOOL)handleOpenURL:(NSURL *)URL sourceApplication:(NSString *)sourceApplicati
 /** @fn completeSignInFlowWithAccessToken:error:
     @brief Called with the result of a Facebook sign-in attempt. Invokes and clears any pending
         sign in callback block.
-    @param accessToken The Facebook access token, if successful.
+    @param accessToken The Facebook access token, if the Facebook sign-in attempt with tracking enabled is successful.
+    @param idToken The Facebook ID token, if the Facebook Limited Login attempt is successful.
     @param error An error which occurred during the sign-in attempt.
  */
 - (void)completeSignInFlowWithAccessToken:(nullable NSString *)accessToken
+                                  idToken:(nullable NSString *)idToken
                                     error:(nullable NSError *)error {
   if (error) {
     [self callbackWithCredential:nil error:error result:nil];
     return;
   }
-  // Assume accessToken cannot be nil if there's no error.
+  FIRAuthCredential *credential;
+  if (idToken) {
+    NSString *rawNonce = self->_currentNonce;
+    credential = [FIROAuthProvider credentialWithProviderID:FIRFacebookAuthProviderID
+                                                    IDToken:idToken
+                                                   rawNonce:rawNonce];
+  } else {
+  // Assume accessToken cannot be nil if there's no error and idToken is nil.
   NSString *_Nonnull token = (id _Nonnull)accessToken;
-  FIRAuthCredential *credential = [FIRFacebookAuthProvider credentialWithAccessToken:token];
+  credential = [FIRFacebookAuthProvider credentialWithAccessToken:token];
+  }
   UIActivityIndicatorView *activityView =
       [FUIAuthBaseViewController addActivityIndicator:_presentingViewController.view];
   [activityView startAnimating];
@@ -347,4 +394,47 @@ - (FBSDKLoginManager *)createLoginManager {
   return [[FBSDKLoginManager alloc] init];
 }
 
+- (NSString *)randomNonce {
+  NSString *characterSet = @"0123456789ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz-._";
+  NSMutableString *result = [NSMutableString string];
+  NSInteger remainingLength = 32;
+
+  while (remainingLength > 0) {
+    NSMutableArray *randoms = [NSMutableArray arrayWithCapacity:16];
+    for (NSInteger i = 0; i < 16; i++) {
+      uint8_t random = 0;
+      int errorCode = SecRandomCopyBytes(kSecRandomDefault, 1, &random);
+      NSAssert(errorCode == errSecSuccess, @"Unable to generate nonce: OSStatus %i", errorCode);
+
+      [randoms addObject:@(random)];
+    }
+
+    for (NSNumber *random in randoms) {
+      if (remainingLength == 0) {
+        break;
+      }
+
+      if (random.unsignedIntValue < characterSet.length) {
+        unichar character = [characterSet characterAtIndex:random.unsignedIntValue];
+        [result appendFormat:@"%C", character];
+        remainingLength--;
+      }
+    }
+  }
+
+  return result;
+}
+
+- (NSString *)stringBySha256HashingString:(NSString *)input {
+  const char *string = [input UTF8String];
+  unsigned char result[CC_SHA256_DIGEST_LENGTH];
+  CC_SHA256(string, (CC_LONG)strlen(string), result);
+
+  NSMutableString *hashed = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH * 2];
+  for (NSInteger i = 0; i < CC_SHA256_DIGEST_LENGTH; i++) {
+    [hashed appendFormat:@"%02x", result[i]];
+  }
+  return hashed;
+}
+
 @end
diff --git a/FirebaseFacebookAuthUI/Sources/Public/FirebaseFacebookAuthUI/FUIFacebookAuth.h b/FirebaseFacebookAuthUI/Sources/Public/FirebaseFacebookAuthUI/FUIFacebookAuth.h
index a425f13b970..ae088d38f8f 100644
--- a/FirebaseFacebookAuthUI/Sources/Public/FirebaseFacebookAuthUI/FUIFacebookAuth.h
+++ b/FirebaseFacebookAuthUI/Sources/Public/FirebaseFacebookAuthUI/FUIFacebookAuth.h
@@ -48,6 +48,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, readwrite) FUIButtonAlignment buttonAlignment;
 
+/** @property useLimitedLogin
+    @brief Whether or not Facebook Login should use Limited Login mode.
+ */
+@property(nonatomic, assign) BOOL useLimitedLogin;
+
 /** @fn initWithAuthUI
     @brief Convenience initializer. Uses a default permission of `@[ "email" ]`.
     @param authUI The @c FUIAuth instance that manages this provider.

From dac3ee1daac1208fbf0e937bc2dd1f53f6861abb Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Thu, 29 Jul 2021 11:32:48 -0400
Subject: [PATCH 2/7] Address review comment to use shared utility method for
 nonce and hashing.

---
 .../Sources/FUIFacebookAuth.m                 | 63 +++----------------
 FirebaseOAuthUI/Sources/FUIOAuth.m            |  3 +
 2 files changed, 12 insertions(+), 54 deletions(-)

diff --git a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
index a725edf7a1f..e3a4ec9e1df 100644
--- a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
+++ b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
@@ -20,13 +20,11 @@
 #import <FirebaseAuth/FirebaseAuth.h>
 
 #if SWIFT_PACKAGE
-@import CommonCrypto;
 @import FBSDKCoreKit;
 @import FBSDKLoginKit;
 #else
 #import <FBSDKCoreKit/FBSDKCoreKit.h>
 #import <FBSDKLoginKit/FBSDKLoginKit.h>
-#import <CommonCrypto/CommonCrypto.h>
 #endif // SWIFT_PACKAGE
 
 /** @var kTableName
@@ -70,6 +68,11 @@ @interface FUIFacebookAuth () <FUIAuthProvider>
  */
 @property(nonatomic, strong) FIROAuthProvider *providerForEmulator;
 
+/** @property currentNonce
+    @brief The nonce for the current Facebook Limited Login session, if any.
+ */
+@property(nonatomic, copy, nullable) NSString *currentNonce;
+
 @end
 
 @implementation FUIFacebookAuth {
@@ -88,11 +91,6 @@ @implementation FUIFacebookAuth {
       @brief The email address associated with this account.
    */
   NSString *_email;
-
-  /** @var _currentNonce
-      @brief The current nonce for a Facebook Limited Login sign-in attempt.
-   */
-  NSString *_currentNonce;
 }
 
 + (NSBundle *)bundle {
@@ -200,12 +198,12 @@ - (void)signInWithDefaultValue:(nullable NSString *)defaultValue
 
   if (self.useLimitedLogin) {
     // Facebook Limited Login
-    NSString *nonce = [self randomNonce];
-    self->_currentNonce = nonce;
+    NSString *nonce = [FUIAuthUtils randomNonce];
+    self.currentNonce = nonce;
     FBSDKLoginConfiguration *configuration =
       [[FBSDKLoginConfiguration alloc] initWithPermissions:_scopes
                                                   tracking:FBSDKLoginTrackingLimited
-                                                     nonce:[self stringBySha256HashingString:nonce]];
+                                                     nonce:[FUIAuthUtils stringBySHA256HashingString:nonce]];
     [_loginManager logInFromViewController:presentingViewController
                             configuration:configuration
                                completion:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
@@ -322,7 +320,7 @@ - (void)completeSignInFlowWithAccessToken:(nullable NSString *)accessToken
   }
   FIRAuthCredential *credential;
   if (idToken) {
-    NSString *rawNonce = self->_currentNonce;
+    NSString *rawNonce = self.currentNonce;
     credential = [FIROAuthProvider credentialWithProviderID:FIRFacebookAuthProviderID
                                                     IDToken:idToken
                                                    rawNonce:rawNonce];
@@ -394,47 +392,4 @@ - (FBSDKLoginManager *)createLoginManager {
   return [[FBSDKLoginManager alloc] init];
 }
 
-- (NSString *)randomNonce {
-  NSString *characterSet = @"0123456789ABCDEFGHIJKLMNOPQRSTUVXYZabcdefghijklmnopqrstuvwxyz-._";
-  NSMutableString *result = [NSMutableString string];
-  NSInteger remainingLength = 32;
-
-  while (remainingLength > 0) {
-    NSMutableArray *randoms = [NSMutableArray arrayWithCapacity:16];
-    for (NSInteger i = 0; i < 16; i++) {
-      uint8_t random = 0;
-      int errorCode = SecRandomCopyBytes(kSecRandomDefault, 1, &random);
-      NSAssert(errorCode == errSecSuccess, @"Unable to generate nonce: OSStatus %i", errorCode);
-
-      [randoms addObject:@(random)];
-    }
-
-    for (NSNumber *random in randoms) {
-      if (remainingLength == 0) {
-        break;
-      }
-
-      if (random.unsignedIntValue < characterSet.length) {
-        unichar character = [characterSet characterAtIndex:random.unsignedIntValue];
-        [result appendFormat:@"%C", character];
-        remainingLength--;
-      }
-    }
-  }
-
-  return result;
-}
-
-- (NSString *)stringBySha256HashingString:(NSString *)input {
-  const char *string = [input UTF8String];
-  unsigned char result[CC_SHA256_DIGEST_LENGTH];
-  CC_SHA256(string, (CC_LONG)strlen(string), result);
-
-  NSMutableString *hashed = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH * 2];
-  for (NSInteger i = 0; i < CC_SHA256_DIGEST_LENGTH; i++) {
-    [hashed appendFormat:@"%02x", result[i]];
-  }
-  return hashed;
-}
-
 @end
diff --git a/FirebaseOAuthUI/Sources/FUIOAuth.m b/FirebaseOAuthUI/Sources/FUIOAuth.m
index c349ff49f7d..056fdaa8b96 100644
--- a/FirebaseOAuthUI/Sources/FUIOAuth.m
+++ b/FirebaseOAuthUI/Sources/FUIOAuth.m
@@ -99,6 +99,9 @@ @interface FUIOAuth () <ASAuthorizationControllerDelegate, ASAuthorizationContro
  */
 @property(nonatomic, copy, nullable) NSString *loginHintKey;
 
+/** @property currentNonce
+    @brief The nonce for the current Sign in with Apple session, if any.
+ */
 @property(nonatomic, copy, nullable) NSString *currentNonce;
 
 /** @property provider

From d0f1c231414782a946fcad2390612851c4266089 Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Thu, 29 Jul 2021 14:47:33 -0400
Subject: [PATCH 3/7] Fix and update demo app.

---
 .../Sources/FUIFacebookAuth.m                 |  8 ++---
 .../FirebaseUI-demo-objc/FUIAppDelegate.m     |  6 ++++
 .../Resources/Main.storyboard                 | 31 ++++++++++++++-----
 .../Samples/Auth/FUIAuthViewController.m      |  8 +++--
 4 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
index e3a4ec9e1df..df6541cb8f4 100644
--- a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
+++ b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
@@ -304,7 +304,7 @@ - (BOOL)handleOpenURL:(NSURL *)URL sourceApplication:(NSString *)sourceApplicati
 
 #pragma mark -
 
-/** @fn completeSignInFlowWithAccessToken:error:
+/** @fn completeSignInFlowWithAccessToken:idToken:error:
     @brief Called with the result of a Facebook sign-in attempt. Invokes and clears any pending
         sign in callback block.
     @param accessToken The Facebook access token, if the Facebook sign-in attempt with tracking enabled is successful.
@@ -325,9 +325,9 @@ - (void)completeSignInFlowWithAccessToken:(nullable NSString *)accessToken
                                                     IDToken:idToken
                                                    rawNonce:rawNonce];
   } else {
-  // Assume accessToken cannot be nil if there's no error and idToken is nil.
-  NSString *_Nonnull token = (id _Nonnull)accessToken;
-  credential = [FIRFacebookAuthProvider credentialWithAccessToken:token];
+    // Assume accessToken cannot be nil if there's no error and idToken is nil.
+    NSString *_Nonnull token = (id _Nonnull)accessToken;
+    credential = [FIRFacebookAuthProvider credentialWithAccessToken:token];
   }
   UIActivityIndicatorView *activityView =
       [FUIAuthBaseViewController addActivityIndicator:_presentingViewController.view];
diff --git a/samples/objc/FirebaseUI-demo-objc/FUIAppDelegate.m b/samples/objc/FirebaseUI-demo-objc/FUIAppDelegate.m
index 7b5bc915b49..4b45cb8f811 100644
--- a/samples/objc/FirebaseUI-demo-objc/FUIAppDelegate.m
+++ b/samples/objc/FirebaseUI-demo-objc/FUIAppDelegate.m
@@ -18,6 +18,7 @@
 
 @import Firebase;
 @import FirebaseAuthUI;
+@import FBSDKCoreKit;
 #import <GTMSessionFetcher/GTMSessionFetcherLogging.h>
 
 @implementation FUIAppDelegate
@@ -26,6 +27,8 @@ - (BOOL)application:(UIApplication *)application
 didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   [FIRApp configure];
   [GTMSessionFetcher setLoggingEnabled:YES];
+  [[FBSDKApplicationDelegate sharedInstance] application:application
+                           didFinishLaunchingWithOptions:launchOptions];
   return YES;
 }
 
@@ -33,6 +36,9 @@ - (BOOL)application:(UIApplication *)app
             openURL:(NSURL *)url
             options:(NSDictionary<NSString*, id> *)options {
   NSString *sourceApplication = options[UIApplicationOpenURLOptionsSourceApplicationKey];
+  [[FBSDKApplicationDelegate sharedInstance] application:app
+                                                 openURL:url
+                                                 options:options];
   return [self handleOpenUrl:url sourceApplication:sourceApplication];
 }
 
diff --git a/samples/objc/FirebaseUI-demo-objc/Resources/Main.storyboard b/samples/objc/FirebaseUI-demo-objc/Resources/Main.storyboard
index 2502ad19938..7e3485f5983 100644
--- a/samples/objc/FirebaseUI-demo-objc/Resources/Main.storyboard
+++ b/samples/objc/FirebaseUI-demo-objc/Resources/Main.storyboard
@@ -1,9 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="15400" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="7RW-VL-qNI">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="17701" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="7RW-VL-qNI">
     <device id="retina4_7" orientation="portrait" appearance="light"/>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="15404"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="17703"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
@@ -162,7 +162,7 @@
                                                 <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Custom Authorization UI" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" minimumFontSize="9" translatesAutoresizingMaskIntoConstraints="NO" id="YxK-c8-9q7">
                                                     <rect key="frame" x="27" y="12" width="322" height="20"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="16"/>
-                                                    <color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
+                                                    <color key="textColor" systemColor="darkTextColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
                                                 <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="JZd-6c-Soe">
@@ -191,7 +191,7 @@
                                                 <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Custom Scopes" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" minimumFontSize="9" translatesAutoresizingMaskIntoConstraints="NO" id="T07-wL-pGr">
                                                     <rect key="frame" x="27" y="12" width="322" height="20"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="16"/>
-                                                    <color key="textColor" cocoaTouchSystemColor="darkTextColor"/>
+                                                    <color key="textColor" systemColor="darkTextColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
                                                 <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" translatesAutoresizingMaskIntoConstraints="NO" id="9Ma-Mx-g56">
@@ -225,14 +225,14 @@
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
-                                                <label opaque="NO" userInteractionEnabled="NO" alpha="0.80000000000000004" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" ambiguous="YES" text="Link" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ig5-8M-jHk">
+                                                <label opaque="NO" userInteractionEnabled="NO" alpha="0.80000000000000004" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Link" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="ig5-8M-jHk">
                                                     <rect key="frame" x="244" y="10.5" width="48" height="21"/>
                                                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="12"/>
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
-                                                <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" ambiguous="YES" contentHorizontalAlignment="center" contentVerticalAlignment="center" on="YES" translatesAutoresizingMaskIntoConstraints="NO" id="LiB-gr-jDR">
+                                                <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" on="YES" translatesAutoresizingMaskIntoConstraints="NO" id="LiB-gr-jDR">
                                                     <rect key="frame" x="300" y="5.5" width="49" height="31"/>
                                                     <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                                                     <connections>
@@ -273,6 +273,17 @@
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
+                                                <label opaque="NO" userInteractionEnabled="NO" alpha="0.80000000000000004" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Limited" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="XLV-Sd-fV6">
+                                                    <rect key="frame" x="244" y="11.5" width="48" height="21"/>
+                                                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                                    <fontDescription key="fontDescription" type="system" pointSize="12"/>
+                                                    <nil key="textColor"/>
+                                                    <nil key="highlightedColor"/>
+                                                </label>
+                                                <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" on="YES" translatesAutoresizingMaskIntoConstraints="NO" id="H4b-GH-bc7" userLabel="Facebook Switch">
+                                                    <rect key="frame" x="300" y="6.5" width="49" height="31"/>
+                                                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                                </switch>
                                             </subviews>
                                         </tableViewCellContentView>
                                     </tableViewCell>
@@ -537,6 +548,7 @@
                         <outlet property="customScopeSwitch" destination="9Ma-Mx-g56" id="Scy-Do-CrR"/>
                         <outlet property="emailLabel" destination="ig5-8M-jHk" id="a2T-8z-dxJ"/>
                         <outlet property="emailSwitch" destination="LiB-gr-jDR" id="I2g-oL-ZRC"/>
+                        <outlet property="facebookSwitch" destination="H4b-GH-bc7" id="z4w-iM-AYz"/>
                     </connections>
                 </tableViewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="1w1-3x-wCC" userLabel="First Responder" sceneMemberID="firstResponder"/>
@@ -561,7 +573,7 @@
                             <view contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="jIg-6e-k6g">
                                 <rect key="frame" x="0.0" y="617" width="375" height="50"/>
                                 <subviews>
-                                    <button opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="1000" horizontalCompressionResistancePriority="1000" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="T3i-kj-emg">
+                                    <button opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="1000" horizontalCompressionResistancePriority="1000" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="T3i-kj-emg">
                                         <rect key="frame" x="333" y="8" width="34" height="34"/>
                                         <state key="normal" title="Load"/>
                                         <connections>
@@ -608,4 +620,9 @@
             <point key="canvasLocation" x="2377" y="315"/>
         </scene>
     </scenes>
+    <resources>
+        <systemColor name="darkTextColor">
+            <color white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+        </systemColor>
+    </resources>
 </document>
diff --git a/samples/objc/FirebaseUI-demo-objc/Samples/Auth/FUIAuthViewController.m b/samples/objc/FirebaseUI-demo-objc/Samples/Auth/FUIAuthViewController.m
index b5537ac98a0..b018ebdc586 100644
--- a/samples/objc/FirebaseUI-demo-objc/Samples/Auth/FUIAuthViewController.m
+++ b/samples/objc/FirebaseUI-demo-objc/Samples/Auth/FUIAuthViewController.m
@@ -64,6 +64,7 @@ @interface FUIAuthViewController () <FUIAuthDelegate>
 @property (weak, nonatomic) IBOutlet UITableViewCell *cellEmail;
 @property (weak, nonatomic) IBOutlet UISwitch *emailSwitch;
 @property (weak, nonatomic) IBOutlet UILabel *emailLabel;
+@property (weak, nonatomic) IBOutlet UISwitch *facebookSwitch;
 @property (weak, nonatomic) IBOutlet UITableViewCell *cellUID;
 @property (weak, nonatomic) IBOutlet UITableViewCell *anonymousSignIn;
 @property (weak, nonatomic) IBOutlet UIBarButtonItem *buttonAuthorization;
@@ -375,12 +376,14 @@ - (void)showAlertWithTitlte:(NSString *)title message:(NSString *)message {
 - (NSArray *)getListOfIDPs {
   return [[self class] getListOfIDPs:[self.tableView indexPathsForSelectedRows]
                      useCustomScopes:_customScopeSwitch.isOn
-                        useEmailLink:_emailSwitch.isOn];
+                        useEmailLink:_emailSwitch.isOn
+          useFacebookLimitedLogin:_facebookSwitch.isOn];
 }
 
 + (NSArray *)getListOfIDPs:(NSArray<NSIndexPath *> *)selectedRows
            useCustomScopes:(BOOL)useCustomScopes
-              useEmailLink:(BOOL)useEmaiLink {
+              useEmailLink:(BOOL)useEmaiLink
+   useFacebookLimitedLogin:(BOOL)useLimitedLogin {
   NSMutableArray *providers = [NSMutableArray new];
 
   for (NSIndexPath *indexPath in selectedRows) {
@@ -426,6 +429,7 @@ + (NSArray *)getListOfIDPs:(NSArray<NSIndexPath *> *)selectedRows
                                                                                 @"user_friends",
                                                                                 @"ads_read"]]
                                      :[[FUIFacebookAuth alloc] initWithAuthUI:[FUIAuth defaultAuthUI]];
+          ((FUIFacebookAuth *)provider).useLimitedLogin = useLimitedLogin;
           break;
         case kIDPTwitter:
           provider = [FUIOAuth twitterAuthProvider];

From 8c5e602859a301c7636e4df8b9312cdba0a9c43c Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Thu, 29 Jul 2021 15:03:59 -0400
Subject: [PATCH 4/7] Extract some duplicate code into a helper method.

---
 .../Sources/FUIFacebookAuth.m                 | 68 ++++++++++---------
 1 file changed, 36 insertions(+), 32 deletions(-)

diff --git a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
index df6541cb8f4..626e76117ae 100644
--- a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
+++ b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
@@ -207,46 +207,32 @@ - (void)signInWithDefaultValue:(nullable NSString *)defaultValue
     [_loginManager logInFromViewController:presentingViewController
                             configuration:configuration
                                completion:^(FBSDKLoginManagerLoginResult *result, NSError *error) {
-      if (error) {
-        NSError *newError =
-            [FUIAuthErrorUtils providerErrorWithUnderlyingError:error
-                                                       providerID:FIRFacebookAuthProviderID];
-        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
-      } else if (result.isCancelled) {
-        NSError *newError = [FUIAuthErrorUtils userCancelledSignInError];
-        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
-      } else {
-        self->_email = FBSDKProfile.currentProfile.email;
-        NSString *idToken = FBSDKAuthenticationToken.currentAuthenticationToken.tokenString;
-        [self completeSignInFlowWithAccessToken:nil idToken:idToken error:nil];
+      if ([self maybeHandleCancelledResult:result error:error]) {
+        return;
       }
+      self->_email = FBSDKProfile.currentProfile.email;
+      NSString *idToken = FBSDKAuthenticationToken.currentAuthenticationToken.tokenString;
+      [self completeSignInFlowWithAccessToken:nil idToken:idToken error:nil];
     }];
   } else {
     [_loginManager logInWithPermissions:_scopes
                      fromViewController:presentingViewController
                                 handler:^(FBSDKLoginManagerLoginResult *result,
                                           NSError *error) {
-      if (error) {
-        NSError *newError =
-        [FUIAuthErrorUtils providerErrorWithUnderlyingError:error
-                                                 providerID:FIRFacebookAuthProviderID];
-        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
-      } else if (result.isCancelled) {
-        NSError *newError = [FUIAuthErrorUtils userCancelledSignInError];
-        [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
-      } else {
-        // Retrieve email.
-        [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me"
-                                           parameters:@{ @"fields" : @"email" }]
-                                  startWithCompletion:^(id<FBSDKGraphRequestConnecting> connection,
-                                                        id result,
-                                                        NSError *error) {
-          self->_email = result[@"email"];
-        }];
-        [self completeSignInFlowWithAccessToken:result.token.tokenString
-                                        idToken:nil
-                                          error:nil];
+      if ([self maybeHandleCancelledResult:result error:error]) {
+        return;
       }
+      // Retrieve email.
+      [[[FBSDKGraphRequest alloc] initWithGraphPath:@"me"
+                                         parameters:@{ @"fields" : @"email" }]
+                                startWithCompletion:^(id<FBSDKGraphRequestConnecting> connection,
+                                                      id result,
+                                                      NSError *error) {
+        self->_email = result[@"email"];
+      }];
+      [self completeSignInFlowWithAccessToken:result.token.tokenString
+                                      idToken:nil
+                                        error:nil];
     }];
   }
 }
@@ -392,4 +378,22 @@ - (FBSDKLoginManager *)createLoginManager {
   return [[FBSDKLoginManager alloc] init];
 }
 
+- (BOOL)maybeHandleCancelledResult:(FBSDKLoginManagerLoginResult *)result
+                             error:(NSError *)error {
+  if (error) {
+    NSError *newError =
+        [FUIAuthErrorUtils providerErrorWithUnderlyingError:error
+                                                   providerID:FIRFacebookAuthProviderID];
+    [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
+    return true;
+  }
+
+  if (result.isCancelled) {
+    NSError *newError = [FUIAuthErrorUtils userCancelledSignInError];
+    [self completeSignInFlowWithAccessToken:nil idToken:nil error:newError];
+    return true;
+  }
+  return false;
+}
+
 @end

From 18f04f668ed15ca32b483d379b0237f7f133c6c9 Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Fri, 30 Jul 2021 10:12:10 -0400
Subject: [PATCH 5/7] Fix Facebook Login in Swift sample app.

---
 .../swift/FirebaseUI-demo-swift/FUIAppDelegate.swift  | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/samples/swift/FirebaseUI-demo-swift/FUIAppDelegate.swift b/samples/swift/FirebaseUI-demo-swift/FUIAppDelegate.swift
index 1c158e0b6d0..84573e5977c 100644
--- a/samples/swift/FirebaseUI-demo-swift/FUIAppDelegate.swift
+++ b/samples/swift/FirebaseUI-demo-swift/FUIAppDelegate.swift
@@ -15,6 +15,7 @@
 //
 
 import UIKit
+import FBSDKCoreKit
 import Firebase
 import FirebaseAuthUI
 import GTMSessionFetcher
@@ -29,11 +30,21 @@ class AppDelegate: UIResponder, UIApplicationDelegate {
     // accompanying valid GoogleService-Info.plist file.
     FirebaseApp.configure()
     GTMSessionFetcher.setLoggingEnabled(true)
+    ApplicationDelegate.shared.application(
+        application,
+        didFinishLaunchingWithOptions: launchOptions
+    )
     return true
   }
   
   @available(iOS 9.0, *)
   func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any]) -> Bool {
+    ApplicationDelegate.shared.application(
+        app,
+        open: url,
+        sourceApplication: options[UIApplication.OpenURLOptionsKey.sourceApplication] as? String,
+        annotation: options[UIApplication.OpenURLOptionsKey.annotation]
+    )
     let sourceApplication = options[UIApplication.OpenURLOptionsKey.sourceApplication] as! String?
     return self.handleOpenUrl(url, sourceApplication: sourceApplication)
   }

From 1ffbd9d03df4f814cf386063e2d1cfe1329b574e Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Fri, 30 Jul 2021 10:45:06 -0400
Subject: [PATCH 6/7] Add Facebook Limited Login to Swift demo app.

---
 .../Resources/Main.storyboard                 | 36 ++++++++++++++-----
 .../Samples/Auth/FUIAuthViewController.swift  |  3 ++
 2 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/samples/swift/FirebaseUI-demo-swift/Resources/Main.storyboard b/samples/swift/FirebaseUI-demo-swift/Resources/Main.storyboard
index e4e71dbff18..5120d178eaa 100644
--- a/samples/swift/FirebaseUI-demo-swift/Resources/Main.storyboard
+++ b/samples/swift/FirebaseUI-demo-swift/Resources/Main.storyboard
@@ -1,9 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="15701" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="jBB-7b-HHb">
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="17701" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="jBB-7b-HHb">
     <device id="retina4_7" orientation="portrait" appearance="light"/>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="15703"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="17703"/>
+        <capability name="System colors in document resources" minToolsVersion="11.0"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
@@ -21,7 +22,7 @@
                         <subviews>
                             <tableView clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="prototypes" style="plain" separatorStyle="default" rowHeight="60" sectionHeaderHeight="1" sectionFooterHeight="1" translatesAutoresizingMaskIntoConstraints="NO" id="EMf-5k-tRY">
                                 <rect key="frame" x="0.0" y="44" width="375" height="623"/>
-                                <color key="backgroundColor" systemColor="systemBackgroundColor" cocoaTouchSystemColor="whiteColor"/>
+                                <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                                 <prototypes>
                                     <tableViewCell clipsSubviews="YES" contentMode="scaleToFill" selectionStyle="blue" hidesAccessoryWhenEditing="NO" indentationLevel="1" indentationWidth="0.0" reuseIdentifier="SamplesViewControllerCell" id="mwf-Pe-7Xw" customClass="SampleCell" customModule="FirebaseUI_demo_swift">
                                         <rect key="frame" x="0.0" y="28" width="375" height="60"/>
@@ -31,13 +32,13 @@
                                             <autoresizingMask key="autoresizingMask"/>
                                             <subviews>
                                                 <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalCompressionResistancePriority="999" text="Subtitle" textAlignment="natural" lineBreakMode="tailTruncation" numberOfLines="0" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="g6W-Ri-8K4">
-                                                    <rect key="frame" x="15" y="41" width="345" height="0.0"/>
+                                                    <rect key="frame" x="16" y="41" width="343" height="0.0"/>
                                                     <fontDescription key="fontDescription" type="system" weight="light" pointSize="12"/>
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
                                                 <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" verticalCompressionResistancePriority="1000" text="Title" textAlignment="natural" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="BZB-4J-Sp6">
-                                                    <rect key="frame" x="15" y="19" width="345" height="14"/>
+                                                    <rect key="frame" x="16" y="19" width="343" height="14"/>
                                                     <fontDescription key="fontDescription" type="system" pointSize="17"/>
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
@@ -61,7 +62,7 @@
                                 </prototypes>
                             </tableView>
                         </subviews>
-                        <color key="backgroundColor" systemColor="systemBackgroundColor" cocoaTouchSystemColor="whiteColor"/>
+                        <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                         <constraints>
                             <constraint firstItem="EMf-5k-tRY" firstAttribute="leading" secondItem="8bC-Xf-vdC" secondAttribute="leading" id="7h5-Xl-YsU"/>
                             <constraint firstItem="wfy-db-euE" firstAttribute="top" secondItem="EMf-5k-tRY" secondAttribute="bottom" id="rqn-rQ-uLD"/>
@@ -151,7 +152,7 @@
                                         <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                         <textInputTraits key="textInputTraits" autocapitalizationType="sentences"/>
                                     </textView>
-                                    <button opaque="NO" contentMode="scaleToFill" horizontalCompressionResistancePriority="999" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="dNa-u5-dnp">
+                                    <button opaque="NO" contentMode="scaleToFill" horizontalCompressionResistancePriority="999" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="dNa-u5-dnp">
                                         <rect key="frame" x="331" y="0.0" width="36" height="30"/>
                                         <state key="normal" title="Send"/>
                                     </button>
@@ -197,7 +198,7 @@
                     <tableView key="view" clipsSubviews="YES" contentMode="scaleToFill" alwaysBounceVertical="YES" dataMode="static" style="grouped" separatorStyle="default" allowsMultipleSelection="YES" rowHeight="44" sectionHeaderHeight="1" sectionFooterHeight="1" id="inr-RJ-pbo">
                         <rect key="frame" x="0.0" y="0.0" width="375" height="667"/>
                         <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
-                        <color key="backgroundColor" systemColor="systemBackgroundColor" cocoaTouchSystemColor="whiteColor"/>
+                        <color key="backgroundColor" systemColor="systemBackgroundColor"/>
                         <sections>
                             <tableViewSection headerTitle="Settings" id="0Pr-Kf-qkL">
                                 <cells>
@@ -313,6 +314,17 @@
                                                     <nil key="textColor"/>
                                                     <nil key="highlightedColor"/>
                                                 </label>
+                                                <label opaque="NO" userInteractionEnabled="NO" alpha="0.80000000000000004" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Limited" textAlignment="right" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="acU-fh-9rC" userLabel="Limited">
+                                                    <rect key="frame" x="244" y="11.5" width="48" height="21"/>
+                                                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                                    <fontDescription key="fontDescription" type="system" pointSize="12"/>
+                                                    <nil key="textColor"/>
+                                                    <nil key="highlightedColor"/>
+                                                </label>
+                                                <switch opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="750" verticalHuggingPriority="750" contentHorizontalAlignment="center" contentVerticalAlignment="center" on="YES" translatesAutoresizingMaskIntoConstraints="NO" id="ySC-ib-kGl" userLabel="Facebook Switch">
+                                                    <rect key="frame" x="310" y="6.5" width="49" height="31"/>
+                                                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                                                </switch>
                                             </subviews>
                                         </tableViewCellContentView>
                                     </tableViewCell>
@@ -508,6 +520,7 @@
                         <outlet property="cellUid" destination="S6s-Qd-Z3i" id="exG-YI-qfx"/>
                         <outlet property="customAuthorizationSwitch" destination="VRw-wD-ISl" id="yWY-Tz-wLP"/>
                         <outlet property="customScopesSwitch" destination="S27-fl-DfX" id="XkZ-5Z-dXj"/>
+                        <outlet property="facebookSwitch" destination="ySC-ib-kGl" id="uiE-zS-pv1"/>
                     </connections>
                 </tableViewController>
                 <placeholder placeholderIdentifier="IBFirstResponder" id="24p-6G-GD4" userLabel="First Responder" sceneMemberID="firstResponder"/>
@@ -534,7 +547,7 @@
                                         <fontDescription key="fontDescription" type="system" pointSize="14"/>
                                         <textInputTraits key="textInputTraits" returnKeyType="done"/>
                                     </textField>
-                                    <button opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="500" horizontalCompressionResistancePriority="1000" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="Kgm-uQ-qTg">
+                                    <button opaque="NO" contentMode="scaleToFill" horizontalHuggingPriority="500" horizontalCompressionResistancePriority="1000" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="system" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="Kgm-uQ-qTg">
                                         <rect key="frame" x="325" y="16" width="34" height="30"/>
                                         <state key="normal" title="Load"/>
                                         <connections>
@@ -597,4 +610,9 @@
             <point key="canvasLocation" x="334" y="1023"/>
         </scene>
     </scenes>
+    <resources>
+        <systemColor name="systemBackgroundColor">
+            <color white="1" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+        </systemColor>
+    </resources>
 </document>
diff --git a/samples/swift/FirebaseUI-demo-swift/Samples/Auth/FUIAuthViewController.swift b/samples/swift/FirebaseUI-demo-swift/Samples/Auth/FUIAuthViewController.swift
index 9b6f9688dfa..981fb521788 100644
--- a/samples/swift/FirebaseUI-demo-swift/Samples/Auth/FUIAuthViewController.swift
+++ b/samples/swift/FirebaseUI-demo-swift/Samples/Auth/FUIAuthViewController.swift
@@ -74,6 +74,7 @@ class FUIAuthViewController: UITableViewController {
   @IBOutlet weak var authorizationButton: UIBarButtonItem!
   @IBOutlet weak var customAuthorizationSwitch: UISwitch!
   @IBOutlet weak var customScopesSwitch: UISwitch!
+  @IBOutlet weak var facebookSwitch: UISwitch!
 
 
   override func viewDidLoad() {
@@ -313,6 +314,8 @@ class FUIAuthViewController: UITableViewController {
                                                                                     "user_friends",
                                                                                     "ads_read"])
               : FUIFacebookAuth(authUI: self.authUI!)
+            let facebookProvider = provider as! FUIFacebookAuth
+            facebookProvider.useLimitedLogin = self.facebookSwitch.isOn
           case Providers.Apple.rawValue:
             if #available(iOS 13.0, *) {
               provider = FUIOAuth.appleAuthProvider()

From 0e5697a362a17e20da39d6eaf001181f42756216 Mon Sep 17 00:00:00 2001
From: Rosalyn Tan <rosalyntan@google.com>
Date: Fri, 17 Sep 2021 18:50:02 -0700
Subject: [PATCH 7/7] Make the Facebook ID token available in addition to the
 access token.

---
 FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
index 626e76117ae..93a3db74301 100644
--- a/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
+++ b/FirebaseFacebookAuthUI/Sources/FUIFacebookAuth.m
@@ -136,6 +136,9 @@ - (nullable NSString *)providerID {
   return FIRFacebookAuthProviderID;
 }
 
+/** @fn accessToken:
+    @brief The access token provided by Facebook's login flow.
+ */
 - (nullable NSString *)accessToken {
   if (self.authUI.isEmulatorEnabled) {
     return nil;
@@ -144,10 +147,13 @@ - (nullable NSString *)accessToken {
 }
 
 /** @fn idToken:
-    @brief Facebook doesn't provide User Id Token during sign in flow
+    @brief The ID token provided by Facebook's login flow.
  */
 - (nullable NSString *)idToken {
-  return nil;
+  if (self.authUI.isEmulatorEnabled) {
+    return nil;
+  }
+  return FBSDKAuthenticationToken.currentAuthenticationToken.tokenString;
 }
 
 - (NSString *)shortName {