Merge "Remove $wgUseTeX for checking if editing tools should be shown"

diff --combined includes/EditPage.php
index aefadbe,a71871d..06bdadd
--- 1/includes/EditPage.php
--- 2/includes/EditPage.php
+++ b/includes/EditPage.php
@@@ -1993,6 -1993,9 +1993,6 @@@ class EditPage 
                        $wgOut->addModules( 'mediawiki.action.edit.editWarning' );
                }
  
 -              // Bug #19334: textarea jumps when editing articles in IE8
 -              $wgOut->addStyle( 'common/IE80Fixes.css', 'screen', 'IE 8' );
 -
                $wgOut->setRobotPolicy( 'noindex,nofollow' );
  
                # Enabled article-related sidebar, toplinks, etc.
@@@ -3316,7 -3319,7 +3316,7 @@@ HTM
         */
        static function getEditToolbar() {
                global $wgStylePath, $wgContLang, $wgLang, $wgOut;
-               global $wgUseTeX, $wgEnableUploads, $wgForeignFileRepos;
+               global $wgEnableUploads, $wgForeignFileRepos;
  
                $imagesAvailable = $wgEnableUploads || count( $wgForeignFileRepos );
  
@@@ -3397,7 -3400,7 +3397,7 @@@
                                'tip'    => wfMessage( 'media_tip' )->text(),
                                'key'    => 'M'
                        ) : false,
-                       $wgUseTeX ? array(
+                       class_exists( 'MathRenderer' ) ? array(
                                'image'  => $wgLang->getImageFile( 'button-math' ),
                                'id'     => 'mw-editbutton-math',
                                'open'   => "<math>",