Issue 5090 - Use user stylesheets for element hiding if possible

lib/elemHideHelper.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+/** @module elemHideHelper */
+
 "use strict";
 
 const {RegExpFilter} = require("filterClasses");
 const {ElemHide} = require("elemHide");
 const {checkWhitelisted} = require("whitelisting");
 const {extractHostFromFrame} = require("url");
 const {port} = require("messaging");
 const devtools = require("devtools");
+const info = require("info");
+
+let userStylesheetsSupported = info.platform == "gecko" &&
+                               info.platformVersion.split(".")[0] >= 53;
+
+function hideElements(tabId, frameId, selectors, callback)
+{
+  let code = selectors.join(", ") + "{display: none !important;}";
+
+  chrome.tabs.insertCSS(tabId,
+    {
+      code,
+      cssOrigin: "user",
+      frameId,
+      matchAboutBlank: true
+    },
+    () =>
+    {
+      callback(chrome.runtime.lastError);
+    }
+  );
+}
 
 port.on("get-selectors", (msg, sender) =>
 {
   let selectors;
   let trace = devtools && devtools.hasPanel(sender.page);
 
   if (!checkWhitelisted(sender.page, sender.frame,
                         RegExpFilter.typeMap.DOCUMENT |
                         RegExpFilter.typeMap.ELEMHIDE))
   {
     let specificOnly = checkWhitelisted(sender.page, sender.frame,
                                         RegExpFilter.typeMap.GENERICHIDE);
     selectors = ElemHide.getSelectorsForDomain(
       extractHostFromFrame(sender.frame),
       specificOnly ? ElemHide.SPECIFIC_ONLY : ElemHide.ALL_MATCHING
     );
   }
   else
   {
     selectors = [];
   }
 
-  return {selectors, trace};
+  if (!userStylesheetsSupported)
+    return {selectors, trace, inject: true};
+
+  if (selectors.length == 0)
+  {
+    if (trace)
+      return {selectors, trace, inject: false};
+
+    return {trace, inject: false};
+  }
+
+  return new Promise(resolve =>
+  {
+    hideElements(sender.page.id, sender.frame.id, selectors, error =>
+    {
+      let response = {trace, inject: !!error};
+
+      if (trace || error)
+        response.selectors = selectors;
+
+      resolve(response);
+    });
+  });
 });
 
-port.on("forward", (msg, sender) =>
+port.on("hide-elements", (msg, sender) =>
 {
-  let targetPage;
-  if (msg.targetPageId)
-    targetPage = ext.getPage(msg.targetPageId);
-  else
-    targetPage = sender.page;
+  if (!msg.selectors || msg.selectors.length == 0)
+    return {success: true};
 
-  if (targetPage)
+  return new Promise(resolve =>
   {
-    msg.payload.sender = sender.page.id;
-    if (msg.expectsResponse)
-      return new Promise(targetPage.sendMessage.bind(targetPage, msg.payload));
-    targetPage.sendMessage(msg.payload);
-  }
+    hideElements(sender.page.id, sender.frame.id, msg.selectors, error =>
+    {
+      resolve({success: !error});
+    });
+  });
 });