Basic implementation of showing password fill dialog on page load

components/password_manager/core/browser/password_manager.h

Index: components/password_manager/core/browser/password_manager.h
diff --git a/components/password_manager/core/browser/password_manager.h b/components/password_manager/core/browser/password_manager.h
index 79ba10c3c539922e7cab3d5bfd55abe3bc2ae153..761fbbcda9863d3abfc1d5668804dca8d817a7c4 100644
--- a/components/password_manager/core/browser/password_manager.h
+++ b/components/password_manager/core/browser/password_manager.h
@@ -68,6 +68,22 @@ class PasswordManager : public LoginModel {
                 const autofill::PasswordForm& preferred_match,
                 bool wait_for_username) const;
 
+  // Called by a PasswordFormManager when a page initially loads and it decides
+  // that a form can be autofilled on the page, but a menu of account options
+  // should be shown instead. Similar to Autofill() above, but does not fill; it
+  // only shows a selection of accounts.
+  //
+  // Currently used by the fill-on-account-select experiment only. See
+  // https://crbug.com/568713.
+  void ShowInitialPasswordAccountSuggestions(
+      password_manager::PasswordManagerDriver* driver,
+      const autofill::PasswordForm& form_for_autofill,
+      const autofill::PasswordFormMap& best_matches,
+      const std::vector<std::unique_ptr<autofill::PasswordForm>>&
+          federated_matches,
+      const autofill::PasswordForm& preferred_match,
+      bool wait_for_username) const;
+
   // Called by a PasswordFormManager when it decides a HTTP auth dialog can be
   // autofilled.
   void AutofillHttpAuth(const autofill::PasswordFormMap& best_matches,