Issue 5864 - Remove previous style sheet before adding one

include.preload.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 326 matching lines @@
     this.observer.disconnect();
     clearTimeout(this.timeout);
   }
 };
 
 function ElemHide()
 {
   this.shadow = this.createShadowTree();
   this.styles = new Map();
   this.tracer = null;
   this.inline = true;

[kzar, 2018/01/24 14:30:53]

How come you renamed this one? (I'm not against renaming it, just curious
really.)

[Manish Jethani, 2018/01/24 16:37:44]

Yeah, this was for clarity [1] since we already use "inject" for tabs.insertCSS

[1]: https://codereview.adblockplus.org/29575739/#msg6

[kzar, 2018/01/25 11:52:37]

Acknowledged.

   this.emulatedPatterns = null;
 
   this.elemHideEmulation = new ElemHideEmulation(
     this.addSelectors.bind(this),
     this.hideElements.bind(this)
   );
 }
 ElemHide.prototype = {
   selectorGroupSize: 200,
 
@@ skipping 14 matching lines @@
     // Finally since some users have both AdBlock and Adblock Plus installed we
     // have to consider how the two extensions interact. For example we want to
     // avoid creating the shadowRoot twice.
     let shadow = document.documentElement.shadowRoot ||
                  document.documentElement.createShadowRoot();
     shadow.appendChild(document.createElement("shadow"));
 
     return shadow;
   },
 
-  addSelectorsInline(selectors, filters, groupName)

[kzar, 2018/01/24 14:30:53]

Just me or is the `filters` parameter not used?

[Manish Jethani, 2018/01/24 16:37:44]

True, removed.

+  addSelectorsInline(selectors, groupName)
   {
     let style = this.styles.get(groupName);
 
     if (style)
     {
       while (style.sheet.cssRules.length > 0)
         style.sheet.deleteRule(0);
     }
 
     if (selectors.length == 0)
@@ skipping 58 matching lines @@
     {
       // Insert the style rules inline if we have been instructed by the
       // 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"
       });
     }
 
@@ skipping 23 matching lines @@
       if (this.tracer)
         this.tracer.disconnect();
       this.tracer = null;
 
       if (response.trace)
         this.tracer = new ElementHidingTracer();
 
       this.inline = response.inline;
 
       if (this.inline)
-        this.addSelectorsInline(response.selectors);

[kzar, 2018/01/24 14:30:53]

Shouldn't we pass the other parameters (well `groupName` anyway) here too?

[Manish Jethani, 2018/01/24 16:37:44]

Yeah so the default group is undefined. We could just use an explicit name here
like "default" or something.

[kzar, 2018/01/25 11:52:37]

Yea, I think making the name here explicit would make the code a little more
obvious.

[Manish Jethani, 2018/01/25 14:29:33]

OK, I'm using the name "standard" here since these are standard CSS selectors,
we just use them as they are in the filters.

+        this.addSelectorsInline(response.selectors, "standard");
 
       if (this.tracer)
         this.tracer.addSelectors(response.selectors);
 
       this.elemHideEmulation.apply(response.emulatedPatterns);
     });
   }
 };
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
 
   elemhide = new ElemHide();
   elemhide.apply();
 
   document.addEventListener("error", event =>
   {
     checkCollapse(event.target);
   }, true);
 
   document.addEventListener("load", event =>
   {
     let element = event.target;
     if (/^i?frame$/.test(element.localName))
       checkCollapse(element);
   }, true);
 }
 
-module.exports = {
-  checkCollapse,
-  elemhide,
-  typeMap,
-  getURLsFromElement
-};
+window.checkCollapse = checkCollapse;
+window.elemhide = elemhide;
+window.typeMap = typeMap;
+window.getURLsFromElement = getURLsFromElement;