[Password Manager] Modified to support saving passwords on forms without username fields.

components/password_manager/core/browser/password_form_manager.cc

Index: components/password_manager/core/browser/password_form_manager.cc
diff --git a/components/password_manager/core/browser/password_form_manager.cc b/components/password_manager/core/browser/password_form_manager.cc
index 84443fa6dbce3ad02170f5c0ef69a8f32b4ebc49..a997303828f499f043c2fec05f1813aecda4435b 100644
--- a/components/password_manager/core/browser/password_form_manager.cc
+++ b/components/password_manager/core/browser/password_form_manager.cc
@@ -226,9 +226,8 @@ bool PasswordFormManager::HasValidPasswordForm() {
   // do not contain username_element and password_element values.
   if (observed_form_.scheme != PasswordForm::SCHEME_HTML)
     return true;
-  return !observed_form_.username_element.empty() &&
-         (!observed_form_.password_element.empty() ||
-          !observed_form_.new_password_element.empty());
+  return !observed_form_.password_element.empty() ||
+         !observed_form_.new_password_element.empty();
 }
 
 void PasswordFormManager::ProvisionallySave(