Issue 5315 - Add support for Microsoft Edge

ext/popup.js

 "use strict";
 
 (function()
 {
+  if ((typeof chrome == "undefined") ||
+      (typeof chrome.extension == "undefined"))

[Sebastian Noack, 2017/06/07 14:42:14]

Why is explicit checking for chrome.extension necessary?

[Oleksandr, 2017/06/14 03:41:01]

There is a 'chrome' object defined in Edge, which has only one property 'app'.

[Sebastian Noack, 2017/06/14 05:13:38]

That's why we only check for `typeof chrome.extension` in ext/common.js, now, I
guess. Can we perhaps make the check here consistent?

+    chrome = browser;

[Sebastian Noack, 2017/06/07 14:42:14]

Is this variable meant to be global? If so, we should probably assign to
window.chrome like we do elsewhere. If we only need it for the line below,
consider using a local variable.

[Oleksandr, 2017/06/14 03:41:01]

Done.

   const backgroundPage = chrome.extension.getBackgroundPage();
   window.ext = Object.create(backgroundPage.ext);
 
   window.ext.closePopup = () =>
   {
     window.close();
   };
 
   // We have to override ext.backgroundPage, because in order
   // to send messages the local "chrome" namespace must be used.
   window.ext.backgroundPage = {
     sendMessage: chrome.runtime.sendMessage,
 
     getWindow()
     {
       return backgroundPage;
     }
   };
 }());