Adds error handling for ERROR_USER_CANCELLED for cpp wrapper.

PiperOrigin-RevId: 277377930

Author: Googler

auth/src/android/common_android.cc

@@ -115,6 +115,7 @@ static const ErrorCodeMapping kFirebaseAuthCodes[] = {
     {"ERROR_UNSUPPORTED_FIRST_FACTOR", kAuthErrorUnsupportedFirstFactor},
     {"ERROR_EMAIL_CHANGE_NEEDS_VERIFICATION",
      kAuthErrorEmailChangeNeedsVerification},
+    {"ERROR_USER_CANCELLED", kAuthErrorMissingOrInvalidNonce},
     {nullptr},
 };
 

auth/src/include/firebase/auth/types.h

@@ -416,6 +416,11 @@ enum AuthError {
   /// This can happen if the hash of the provided raw nonce did not match the
   /// hashed nonce in the OIDC ID token payload.
   kAuthErrorMissingOrInvalidNonce,
+
+  /// Indicates that the user did not authorize the application during Generic
+  /// IDP sign-in.
+  kAuthErrorUserCancelled,
+
 #endif  // INTERNAL_EXEPERIMENTAL
 };