Use an MutationObserver to check when a password form disappears after XHR

components/autofill/content/common/autofill_types_struct_traits.cc

Index: components/autofill/content/common/autofill_types_struct_traits.cc
diff --git a/components/autofill/content/common/autofill_types_struct_traits.cc b/components/autofill/content/common/autofill_types_struct_traits.cc
index 7a4b19a33fc1508926fae980f8e632e38ebef38f..52373e3329494210a065b6750a3262ca4fe2f4e6 100644
--- a/components/autofill/content/common/autofill_types_struct_traits.cc
+++ b/components/autofill/content/common/autofill_types_struct_traits.cc
@@ -261,6 +261,9 @@ EnumTraits<mojom::PasswordFormSubmissionIndicatorEvent,
       return mojom::PasswordFormSubmissionIndicatorEvent::FRAME_DETACHED;
     case PasswordForm::SubmissionIndicatorEvent::MANUAL_SAVE:
       return mojom::PasswordFormSubmissionIndicatorEvent::MANUAL_SAVE;
+    case PasswordForm::SubmissionIndicatorEvent::DOM_MUTATION_AFTER_XHR:
+      return mojom::PasswordFormSubmissionIndicatorEvent::
+          DOM_MUTATION_AFTER_XHR;
     case PasswordForm::SubmissionIndicatorEvent::
         SUBMISSION_INDICATOR_EVENT_COUNT:
       return mojom::PasswordFormSubmissionIndicatorEvent::
@@ -296,6 +299,9 @@ bool EnumTraits<mojom::PasswordFormSubmissionIndicatorEvent,
     case mojom::PasswordFormSubmissionIndicatorEvent::MANUAL_SAVE:
       *output = PasswordForm::SubmissionIndicatorEvent::MANUAL_SAVE;
       return true;
+    case mojom::PasswordFormSubmissionIndicatorEvent::DOM_MUTATION_AFTER_XHR:
+      *output = PasswordForm::SubmissionIndicatorEvent::DOM_MUTATION_AFTER_XHR;
+      return true;
     case mojom::PasswordFormSubmissionIndicatorEvent::
         SUBMISSION_INDICATOR_EVENT_COUNT:
       *output = PasswordForm::SubmissionIndicatorEvent::