Removes unused events.

JitsiTrackErrors.js

         }
     },
     UNSUPPORTED_RESOLUTION: "gum.unsupported_resolution",
+    /**
+     * An event which indicates that the jidesha extension for Firefox is
+     * needed to proceed with screen sharing, and that it is not installed.
+     */
     FIREFOX_EXTENSION_NEEDED: "gum.firefox_extension_needed",
     CHROME_EXTENSION_INSTALLATION_ERROR:
         "gum.chrome_extension_installation_error",

modules/RTC/ScreenObtainer.js

 var logger = require("jitsi-meet-logger").getLogger(__filename);
 var RTCBrowserType = require("./RTCBrowserType");
 var AdapterJS = require("./adapter.screenshare");
-var DesktopSharingEventTypes
-    = require("../../service/desktopsharing/DesktopSharingEventTypes");
 var JitsiTrackErrors = require("../../JitsiTrackErrors");
 
 /**

service/desktopsharing/DesktopSharingEventTypes.js

-var DesktopSharingEventTypes = {
-    /**
-     * An event which indicates that the jidesha extension for Firefox is
-     * needed to proceed with screen sharing, and that it is not installed.
-     */
-    FIREFOX_EXTENSION_NEEDED: "ds.firefox_extension_needed"
-};
-
-module.exports = DesktopSharingEventTypes;