title: How to set multiple translation domain for symfony 2 form type
body: <p>I have the fallowing form structure: </p>
  
  <pre><code>abstract class BaseContentType extends AbstractType {
      public function buildForm(FormBuilderInterface $builder, array $options) {
          //common fields
      }
      public function getDefaultOptions() {
          return array(
              'translation_domain' =&gt; 'MyBaseBundle',
              'isNew' =&gt; false,
          );
      }
   }
  
  class SpecializedContentType extends BaseContentType {
      public function buildForm(FormBuilderInterface $builder, array $options) {
          parent::buildForm($builder, $options);
          //more fields....
      }
  
      public function getName() {
          return 'specialized_content';
      }
  
      public function setDefaultOptions(OptionsResolverInterface $resolver) {
          $options = $this-&gt;getDefaultOptions() + array(
              'data_class' =&gt; 'whatever\Entity\Specialized',
          );
          $resolver-&gt;setDefaults($options);
      }
  }
  </code></pre>
  
  <p>I need to have different translation domain for the BaseContentType and for every subclasses.</p>
  
  <p>How can I add separate translation domain for a class and its parent?</p>