Issue 3251 - Simplify messaging from child scripts to parent

lib/child/elemHide.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 19 matching lines @@
 catch (e)
 {
   Cu.reportError(e);
 }
 
 let {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
 
 let {Utils} = require("utils");
 let {getFrames, isPrivate} = require("child/utils");
 
-let messageID = 0;
-
 // The allowXBL binding below won't have any effect on the element. For elements
 // that should be hidden however we don't return any binding at all, this makes
 // Gecko stop constructing the node - it cannot be shown.
 const allowXBL = "<bindings xmlns='http://www.mozilla.org/xbl'><binding id='dummy' bindToUntrustedContent='true'/></bindings>";
 const hideXBL = "<bindings xmlns='http://www.mozilla.org/xbl'/>";
 
 /**
  * about: URL module used to count hits.
  * @class
  */
@@ skipping 72 matching lines @@
   owner: Utils.systemPrincipal,
   securityInfo: null,
   notificationCallbacks: null,
   loadFlags: 0,
   loadGroup: null,
   name: null,
   status: Cr.NS_OK,
 
   asyncOpen: function(listener, context)
   {
-    let responseMessage = "AdblockPlus:ElemHideHit:Response" + (++messageID);
-
-    let processResponse = (message) =>
+    let processResponse = (response) =>
     {
-      removeMessageListener(responseMessage, processResponse);
-
-      let data = (message.data ? hideXBL : allowXBL);
+      let data = (response ? hideXBL : allowXBL);
       let stream = Cc["@mozilla.org/io/string-input-stream;1"].createInstance(Ci.nsIStringInputStream);
       stream.setData(data, data.length);
 
       try {
         listener.onStartRequest(this, context);
       } catch(e) {}
       try {
         listener.onDataAvailable(this, context, stream, 0, stream.available());
       } catch(e) {}
       try {
         listener.onStopRequest(this, context, Cr.NS_OK);
       } catch(e) {}
     };
 
     let window = Utils.getRequestWindow(this);
-    addMessageListener(responseMessage, processResponse);
     sendAsyncMessage("AdblockPlus:ElemHideHit", {
-      responseMessage,
       key: this.key,
       frames: getFrames(window),
       isPrivate: isPrivate(window)
-    });
+    }, processResponse);
   },
 
   asyncOpen2: function(listener)
   {
     if (!this.loadInfo.triggeringPrincipal.equals(Utils.systemPrincipal))
       throw Cr.NS_ERROR_FAILURE;
     this.asyncOpen(listener, null);
   },
 
   open: function()
@@ skipping 12 matching lines @@
   {
     throw Cr.NS_ERROR_NOT_IMPLEMENTED;
   },
   resume: function()
   {
     throw Cr.NS_ERROR_NOT_IMPLEMENTED;
   },
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsIChannel, Ci.nsIRequest])
 };