Record wait_for_username and bail for NewPasswordFormManager

If the NewPasswordFormManager instructs the PasswordAutofillAgent to wait for
the user to confirm filling the password, we need to log this as for the old
PasswordFormManager.

I have verified that the new metrics are recorded and that PSL matched filling
continues to work.

Bug: 918846
Change-Id: I010500bedd0c3a7c462074f2c7dcd70b4cc7a0b4
Reviewed-on: https://chromium-review.googlesource.com/c/1404092
Reviewed-by: Vadym Doroshenko <dvadym@chromium.org>
Commit-Queue: Dominic Battré <battre@chromium.org>
Cr-Commit-Position: refs/heads/master@{#621586}

components/autofill/content/renderer/password_autofill_agent.cc

@@ -1420,6 +1420,14 @@ void PasswordAutofillAgent::FillUsingRendererIDs(
 
   StoreDataForFillOnAccountSelect(form_data, username_element,
                                   password_element);
+
+  // If wait_for_username is true, we don't want to initially fill the form
+  // until the user types in a valid username.
+  if (form_data.wait_for_username) {
+    LogFirstFillingResult(FillingResult::kWaitForUsername);
+    return;
+  }
+
   FillFormOnPasswordReceived(form_data, username_element, password_element,
                              &field_data_manager_, logger.get());
 }