Index: wp-admin/revision.php
===================================================================
--- wp-admin/revision.php (revision 19792)
+++ wp-admin/revision.php (working copy)
@@ -169,8 +169,8 @@
 $identical = true;
 foreach ( _wp_post_revision_fields() as $field => $field_title ) :
  if ( 'diff' == $action ) {
-   $left_content = apply_filters( "_wp_post_revision_field_$field", $left_revision->$field, $field );
-   $right_content = apply_filters( "_wp_post_revision_field_$field", $right_revision->$field, $field );
+   $left_content = apply_filters( "_wp_post_revision_field_$field", $left_revision->$field, $field, $left_revision->ID );
+   $right_content = apply_filters( "_wp_post_revision_field_$field", $right_revision->$field, $field, $right_revision->ID );
    if ( !$content = wp_text_diff( $left_content, $right_content ) )
      continue; // There is no difference between left and right
    $identical = false;