Issue 4364 - Drop support for Chrome 29-40 and remove legacy code

composer.postload.js

Index: composer.postload.js
===================================================================
--- a/composer.postload.js
+++ b/composer.postload.js
@@ -485,11 +485,7 @@
   ext.onExtensionUnloaded.removeListener(deactivateBlockElement);
 }
 
-// In Chrome 37-40, the document_end content script (this one) runs properly,
-// while the document_start content scripts (that defines ext) might not. Check
-// whether variable ext exists before continuing to avoid
-// "Uncaught ReferenceError: ext is not defined". See https://crbug.com/416907
-if ("ext" in window && document instanceof HTMLDocument)
+if (document instanceof HTMLDocument)
 {
   // Use a contextmenu handler to save the last element the user right-clicked
   // on. To make things easier, we actually save the DOM event. We have to do
@@ -553,7 +549,7 @@
           checkCollapse(currentElement.prisoner || currentElement);
 
           // Apply added element hiding filters.
-          updateStylesheet();
+          elemhide.apply();
         }
         deactivateBlockElement();
         break;