Update Confirmation UI for saved password change

components/password_manager/core/browser/password_form_manager.h

Index: components/password_manager/core/browser/password_form_manager.h
diff --git a/components/password_manager/core/browser/password_form_manager.h b/components/password_manager/core/browser/password_form_manager.h
index 0082417b81d88efa13d005b69b0186505ec8fb78..f158b280f9bd9663659fe557f14a7d925bd9fbc1 100644
--- a/components/password_manager/core/browser/password_form_manager.h
+++ b/components/password_manager/core/browser/password_form_manager.h
@@ -145,6 +145,10 @@ class PasswordFormManager : public PasswordStoreConsumer {
   // TODO: Make this private once we switch to the new UI.
   void Save();
 
+  // Update the password store entry for |credentials_to_update|, using the
+  // password from |pending_credentials_|. It modifies |pending_credentials_|.
+  void Update(const autofill::PasswordForm& credentials_to_update);
+
   // Call these if/when we know the form submission worked or failed.
   // These routines are used to update internal statistics ("ActionsTaken").
   void SubmitPassed();
@@ -348,6 +352,13 @@ class PasswordFormManager : public PasswordStoreConsumer {
   // from password store.
   void CreatePendingCredentials();
 
+  // For non-empty |password| returns the unique entry in |best_matches_| with
+  // the same password, if it exists, and nullptr otherwise. For empty
+  // |password|, if there is just one entry in |best_matches_|, returns that
+  // entry, otherwise nullptr.
+  autofill::PasswordForm* FindBestMatchForUpdatePassword(
+      const base::string16& password) const;
+
   // Set of PasswordForms from the DB that best match the form
   // being managed by this. Use a map instead of vector, because we most
   // frequently require lookups by username value in IsNewLogin.