When view mode is 'form' set $extra_fields['webform']['visible'] to 'visible'

Problem/Motivation

webform_node_view() permits the 'form' view mode to force display:
// View mode of 'form' is exempted to allow blocks and views to force display.

However, if the 'form' view mode is passed to webform_node_view(), it may result in an undefined index error. $node->content['webform']['visible'] assumes $extra_fields['webform']['visible'] is set, which isn't necessarily true if the 'form' view mode is used.

  // Add the output to the node.
  $node->content['webform'] = array(
    '#theme' => 'webform_view',
    '#node' => $node,
    '#page' => $page,
    '#form' => $form,
    '#enabled' => $enabled,
    '#visible' => $extra_fields['webform']['visible'], // When 'form' view mode is used, $extra_fields['webform']['visible'] isn't set.
    '#weight' => 10,
  );

Proposed resolution

The proposed solution is to set $extra_fields['webform']['visible'] to TRUE if the 'form' view mode is being used:

  // If the webform is not set to display in this view mode, return early.
  // View mode of 'form' is exempted to allow blocks and views to force display.
  $extra_fields = field_extra_fields_get_display('node', $node->type, $view_mode);
  if ($view_mode != 'form' && empty($extra_fields['webform']['visible'])) {
    return;
  }
+  elseif ($view_mode == 'form') {
+   $extra_fields['webform']['visible'] = TRUE;
+  }

Remaining tasks

None

User interface changes

None

API changes

None

Data model changes

None