Fixes nullability and removed redundant property for FIROAuthCredential. (#262)

* Fixes nullability and removed redundant property for FIROAuthCredential.
* Fixes a typo in FIROAuthCredential initializer.

Author: XiangtianDai

Firebase/Auth/Source/AuthProviders/OAuth/FIROAuthCredential.h

@@ -25,30 +25,25 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @interface FIROAuthCredential : FIRAuthCredential
 
-/** @property providerID
-    @brief The provider ID associated with this credential.
- */
-@property(nonatomic, readonly) NSString *providerID;
-
 /** @property IDToken
     @brief The ID Token associated with this credential.
  */
-@property(nonatomic, readonly) NSString *IDToken;
+@property(nonatomic, readonly, nullable) NSString *IDToken;
 
 /** @property accessToken
     @brief The access token associated with this credential.
  */
-@property(nonatomic, readonly) NSString *accessToken;
+@property(nonatomic, readonly, nullable) NSString *accessToken;
 
 /** @fn initWithProviderId:IDToken:accessToken:
     @brief Designated initializer.
     @param providerID The provider ID associated with the credential being created.
     @param IDToken  The ID Token associated with the credential being created.
     @param accessToken The access token associated with the credential being created.
  */
-- (nullable instancetype)initWithProvierID:(NSString *)providerID
-                                   IDToken:(nullable NSString*)IDToken
-                               accessToken:(nullable NSString *)accessToken;
+- (nullable instancetype)initWithProviderID:(NSString *)providerID
+                                    IDToken:(nullable NSString*)IDToken
+                                accessToken:(nullable NSString *)accessToken;
 
 @end
 

Firebase/Auth/Source/AuthProviders/OAuth/FIROAuthCredential.m

@@ -15,7 +15,7 @@
  */
 
 #import "FIROAuthCredential.h"
-#import "FIRAuthExceptionUtils.h"
+
 #import "FIRVerifyAssertionRequest.h"
 
 NS_ASSUME_NONNULL_BEGIN
@@ -28,12 +28,11 @@ - (nullable instancetype)initWithProvider:(NSString *)provider NS_UNAVAILABLE;
 
 @implementation FIROAuthCredential
 
-- (nullable instancetype)initWithProvierID:(NSString *)providerID
-                                   IDToken:(nullable NSString *)IDToken
-                               accessToken:(nullable NSString *)accessToken {
+- (nullable instancetype)initWithProviderID:(NSString *)providerID
+                                    IDToken:(nullable NSString *)IDToken
+                                accessToken:(nullable NSString *)accessToken {
   self = [super initWithProvider:providerID];
   if (self) {
-    _providerID = providerID;
     _IDToken = IDToken;
     _accessToken = accessToken;
   }

Firebase/Auth/Source/AuthProviders/OAuth/FIROAuthProvider.m

@@ -25,16 +25,16 @@ @implementation FIROAuthProvider
 + (FIRAuthCredential *)credentialWithProviderID:(NSString *)providerID
                                         IDToken:(NSString *)IDToken
                                     accessToken:(nullable NSString *)accessToken {
-  return [[FIROAuthCredential alloc] initWithProvierID:providerID
-                                               IDToken:IDToken
-                                           accessToken:accessToken];
+  return [[FIROAuthCredential alloc] initWithProviderID:providerID
+                                                IDToken:IDToken
+                                            accessToken:accessToken];
 }
 
 + (FIROAuthCredential *)credentialWithProviderID:(NSString *)providerID
                                      accessToken:(NSString *)accessToken {
-  return [[FIROAuthCredential alloc] initWithProvierID:providerID
-                                               IDToken:nil
-                                           accessToken:accessToken];
+  return [[FIROAuthCredential alloc] initWithProviderID:providerID
+                                                IDToken:nil
+                                            accessToken:accessToken];
 }
 
 NS_ASSUME_NONNULL_END