Issue 4802 - Add back compatibility for Microsoft Edge after #4722 removed it

options.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 38 matching lines @@
     if (arguments.length > 0)
     {
       var lastArg = arguments[arguments.length - 1];
       if (typeof lastArg == "function")
         callback = lastArg;
 
       for (var i = 0; i < arguments.length - (callback ? 1 : 0); i++)
         message[paramKeys[i]] = arguments[i];
     }
 
-    // Edge silently fails when sendMessage is called with a callback

[kzar, 2017/01/17 06:54:31]

Did you file an issue for this with Microsoft? (Or is there already an issue?) I
think you should + add a link here. Also could you mention the version of Edge
that the problem happens for here, that will help us when we're considering
removing the workaround in the future.

[Oleksandr, 2017/01/18 03:08:44]

The issue is marked as Fixed, however it is not clear in what release. In
"evergreen browser" reality I guess we should just set up a policy to remove the
workaround no sooner then a predefined period of time (6 months?)

[kzar, 2017/01/18 03:48:41]

OK well add a link to that issue here and also update the comment to mention
which version of Edge sendMessage is silently failing for. I guess we can figure
out the exact version which fixes the issue later after it's released.

-    // parameter of undefined, so we work around that here.
+    // Edge 38.14393 silently fails when sendMessage is called with a callback
+    // parameter of null, so we work around that here.

[kzar, 2017/01/18 04:49:50]

The callback parameter will be `undefined` not `null`, I wonder why you changed
it in the comment?

[Oleksandr, 2017/01/19 20:51:01]

The issue on Microsoft's issue tracker just mentions a null callback. I thought
I'd align the comment. But I can see how that could be confusing. Fixed that in
a followup commit.

+    // https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/8504730/
     if (callback)
       ext.backgroundPage.sendMessage(message, callback);
     else
       ext.backgroundPage.sendMessage(message);
   };
 }
 
 var getDocLink = wrapper({type: "app.get", what: "doclink"}, "link");
 var getInfo = wrapper({type: "app.get"}, "what");
 var getPref = wrapper({type: "prefs.get"}, "key");
@@ skipping 661 matching lines @@
       onFilterMessage(message.action, message.args[0]);
       break;
     case "prefs.respond":
       onPrefMessage(message.action, message.args[0]);
       break;
     case "subscriptions.respond":
       onSubscriptionMessage(message.action, message.args[0]);
       break;
   }
 });