Issue 5864 - Remove previous style sheet before adding one

include.preload.js

Index: include.preload.js
===================================================================
--- a/include.preload.js
+++ b/include.preload.js
@@ -374,17 +374,17 @@
     // avoid creating the shadowRoot twice.
     let shadow = document.documentElement.shadowRoot ||
                  document.documentElement.createShadowRoot();
     shadow.appendChild(document.createElement("shadow"));
 
     return shadow;
   },
 
-  addSelectorsInline(selectors, filters, groupName)
+  addSelectorsInline(selectors, groupName)
   {
     let style = this.styles.get(groupName);
 
     if (style)
     {
       while (style.sheet.cssRules.length > 0)
         style.sheet.deleteRule(0);
     }
@@ -453,17 +453,17 @@
       // background page to do so. This is usually the case, except on platforms
       // that do support user stylesheets via the browser.tabs.insertCSS API
       // (Firefox 53 onwards for now and possibly Chrome in the near future).
       // Once all supported platforms have implemented this API, we can remove
       // the code below. See issue #5090.
       // Related Chrome and Firefox issues:
       // https://bugs.chromium.org/p/chromium/issues/detail?id=632009
       // https://bugzilla.mozilla.org/show_bug.cgi?id=1310026
-      this.addSelectorsInline(selectors, filters, "emulated");
+      this.addSelectorsInline(selectors, "emulated");
     }
     else
     {
       browser.runtime.sendMessage({
         type: "elemhide.injectSelectors",
         selectors,
         groupName: "emulated"
       });