Issue 3108 - Less hacky approach to disabling E10S compatibility shims

lib/utils.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 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 362 matching lines @@
    * Retrieves and removes sidebar state after detaching/reattaching
    */
   getParams: function()
   {
     let ret = sidebarParams;
     sidebarParams = null;
     return ret;
   },
 
   /**
+   * E10S compatibility shims will reroute property retrieval on some objects
+   * in order to enable custom behavior. This cannot be disabled on case by case
+   * basis (see https://bugzilla.mozilla.org/show_bug.cgi?id=1167802). So
+   * instead we use a different execution context to retrieve properties when
+   * E10S compatibility shims shouldn't kick in. This method simply returns
+   * obj[prop] but without any custom behavior.
+   */
+  getPropertyWithoutCompatShims: function(/**Object*/ obj, /**String*/ prop)
+  {
+    let sandbox = Cu.Sandbox(Utils.systemPrincipal);
+    sandbox.obj = obj;
+    sandbox.prop = prop;
+    return Cu.evalInSandbox("obj[prop]", sandbox);
+  },
+
+  /**
    * Verifies RSA signature. The public key and signature should be base64-encoded.
    * @param {string} key
    * @param {string} signature
    * @param {string} data
    * @return {boolean}
    */
   verifySignature: function(key, signature, data)
   {
     if (!Utils.crypto)
       return false;
@@ skipping 373 matching lines @@
     Cu.reportError(e);
     // Expected, ctypes isn't supported in Gecko 1.9.2
     return null;
   }
 });
 
 if ("@mozilla.org/messenger/headerparser;1" in Cc)
   XPCOMUtils.defineLazyServiceGetter(Utils, "headerParser", "@mozilla.org/messenger/headerparser;1", "nsIMsgHeaderParser");
 else
   Utils.headerParser = null;