Issue #2301955 by er.pushpinderrana, lokapujya | scor: Ensure RDFa metadata tags are hidden.

CHANGELOG.txt

@@ -1,6 +1,8 @@
 
 Drupal 7.33, xxxx-xx-xx (development version)
 -----------------------
+- Added an HTML class to RDFa metatags throughout Drupal to prevent them from
+  accidentally affecting the site appearance (minor markup change).
 - Fixed a bug in the Unicode requirements check which prevented installing
   Drupal on PHP 5.6.
 - Fixed a bug which caused drupal_get_bootstrap_phase() to abort the bootstrap

modules/rdf/rdf.module

@@ -865,9 +865,9 @@ function theme_rdf_metadata($variables) {
   $output = '';
   foreach ($variables['metadata'] as $attributes) {
     // Add a class so that developers viewing the HTML source can see why there
-    // are empty <span> tags in the document. The class can also be used to set
-    // a CSS display:none rule in a theme where empty spans affect display.
+    // are empty <span> tags in the document.
     $attributes['class'][] = 'rdf-meta';
+    $attributes['class'][] = 'element-hidden';
     // The XHTML+RDFa doctype allows either <span></span> or <span /> syntax to
     // be used, but for maximum browser compatibility, W3C recommends the
     // former when serving pages using the text/html media type, see