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

components/autofill/core/common/password_form.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_AUTOFILL_CORE_COMMON_PASSWORD_FORM_H__
 #define COMPONENTS_AUTOFILL_CORE_COMMON_PASSWORD_FORM_H__
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 77 matching lines @@
   // potentially being submitted, or that a form has already been successfully
   // submitted. Recorded into a UMA histogram, so order of enumerators should
   // not be changed.
   enum class SubmissionIndicatorEvent {
     NONE,
     HTML_FORM_SUBMISSION,
     SAME_DOCUMENT_NAVIGATION,
     XHR_SUCCEEDED,
     FRAME_DETACHED,
     MANUAL_SAVE,
+    DOM_MUTATION_AFTER_XHR,
     SUBMISSION_INDICATOR_EVENT_COUNT
   };
 
   // The "Realm" for the sign-on. This is scheme, host, port for SCHEME_HTML.
   // Dialog based forms also contain the HTTP realm. Android based forms will
   // contain a string of the form "android://<hash of cert>@<package name>"
   //
   // The signon_realm is effectively the primary key used for retrieving
   // data from the database, so it must not be empty.
   std::string signon_realm;
@@ skipping 226 matching lines @@
 std::ostream& operator<<(std::ostream& os, PasswordForm::Layout layout);
 std::ostream& operator<<(std::ostream& os, const PasswordForm& form);
 std::ostream& operator<<(std::ostream& os, PasswordForm* form);
 std::ostream& operator<<(
     std::ostream& os,
     PasswordForm::SubmissionIndicatorEvent submission_event);
 
 }  // namespace autofill
 
 #endif  // COMPONENTS_AUTOFILL_CORE_COMMON_PASSWORD_FORM_H__