API feature request, lookup cid from known fieldname

Since the webform module checks to prevent the use of duplicate component fieldnames, it would be nice if there were a built-in lookup function as part of the API

// **BEFORE**
function hook_webform_submission_presave($node, &$submission) {
  // Update some component's value before it is saved.
  $component_id = 4;
  $submission->data[$component_id]['value'][0] = 'foo';
}

// **AFTER**
function hook_webform_submission_presave($node, &$submission) {
  // Update some component's value before it is saved.
  $component_id = webform_get_cid_from_fieldname($nid, 'customer_email');
  $submission->data[$component_id]['value'][0] = 'foo@drupal.org';
}

The benefit here is that it is easy to remember the fieldnames you used when you created the webform,
but it is not always easy to remember or keep track of cid values.