Add events to notify Firefox screen sharing extension when screen sharing starts and stops.

static/js/directives/screenshare.js

@@ -172,6 +172,7 @@ define(['jquery', 'underscore', 'text!partials/screenshare.html', 'text!partials
 				}
 
 				$scope.layout.screenshare = true;
+				screensharing.globalNotify().screensharingStart();
 				screensharing.getScreen().then(function(options) {
 					if (options) {
 						$scope.startScreenshare(options);
@@ -307,6 +308,8 @@ define(['jquery', 'underscore', 'text!partials/screenshare.html', 'text!partials
 					$scope.layout.screenshare = false;
 				}
 
+				screensharing.globalNotify().screensharingStop();
+
 			};
 
 			$scope.toggleFullscreen = function(elem) {

static/js/services/screensharing.js

@@ -32,6 +32,9 @@ define(['underscore', 'text!partials/screensharedialogff.html', 'webrtc.adapter'
 		};
 	}];
 
+	var GLOBAL_SCREENSHARING_START_EVENT = new Event('webrtcStartScreensharing');
+	var GLOBAL_SCREENSHARING_STOP_EVENT = new Event('webrtcStopScreensharing');
+
 	// screensharing
 	return ["$window", "$q", "$timeout", "chromeExtension", "dialogs", "$templateCache", function($window, $q, $timeout, chromeExtension, dialogs, $templateCache) {
 
@@ -45,6 +48,17 @@ define(['underscore', 'text!partials/screensharedialogff.html', 'webrtc.adapter'
 			}, this));
 		};
 
+		Screensharing.prototype.globalNotify = function() {
+			return {
+				screensharingStart: function() {
+					$window.dispatchEvent(GLOBAL_SCREENSHARING_START_EVENT);
+				},
+				screensharingStop: function() {
+					$window.dispatchEvent(GLOBAL_SCREENSHARING_STOP_EVENT);
+				}
+			};
+		};
+
 		Screensharing.prototype.initialize = function() {
 
 			// Check if we can do screensharing.