Add extra_params argument to signin call

Author: dan-gulliver

GoogleSignIn/Sources/GIDSignIn.m

@@ -248,15 +248,21 @@ - (void)signInWithPresentingViewController:(UIViewController *)presentingViewCon
 - (void)signInWithPresentingViewController:(UIViewController *)presentingViewController
                                       hint:(nullable NSString *)hint
                           additionalScopes:(nullable NSArray<NSString *> *)additionalScopes
+                          additionalParams:(nullable NSDictionary *)extraParams
                                 completion:(nullable GIDSignInCompletion)completion {
-  GIDSignInInternalOptions *options =
+    GIDSignInInternalOptions *options =
     [GIDSignInInternalOptions defaultOptionsWithConfiguration:_configuration
                                      presentingViewController:presentingViewController
                                                     loginHint:hint
                                                 addScopesFlow:NO
                                                        scopes:additionalScopes
                                                    completion:completion];
-  [self signInWithOptions:options];
+    
+    if (extraParams != nil) {
+        options = [options optionsWithExtraParameters:extraParams forContinuation:NO];
+    }
+    
+    [self signInWithOptions:options];
 }
 
 - (void)signInWithPresentingViewController:(UIViewController *)presentingViewController

GoogleSignIn/Sources/Public/GoogleSignIn/GIDSignIn.h

@@ -160,6 +160,7 @@ typedef NS_ERROR_ENUM(kGIDSignInErrorDomain, GIDSignInErrorCode) {
 - (void)signInWithPresentingViewController:(UIViewController *)presentingViewController
                                       hint:(nullable NSString *)hint
                           additionalScopes:(nullable NSArray<NSString *> *)additionalScopes
+                          additionalParams:(nullable NSDictionary *)extraParams
                                 completion:
     (nullable void (^)(GIDSignInResult *_Nullable signInResult,
                        NSError *_Nullable error))completion