Implements getDisplayMedia when available on chrome.

modules/RTC/RTCUtils.js

@@ -473,6 +473,21 @@ function getSSConstraints(options = {}) {
     return constraints;
 }
 
+/**
+ * Generates constraints for screen sharing when using getDisplayMedia.
+ * The constraints(MediaTrackConstraints) are applied to the resulting track.
+ *
+ * @returns {Object} - MediaTrackConstraints constraints.
+ */
+function getTrackSSConstraints() {
+    // we used to set height and width in the constraints, but this can lead
+    // to inconsistencies if the browser is on a lower resolution screen
+    // and we share a screen with bigger resolution, so they are now not set
+    return {
+        frameRate: SS_DEFAULT_FRAME_RATE
+    };
+}
+
 /**
  * Sets the availbale devices based on the options we requested and the
  * streams we received.
@@ -866,7 +881,8 @@ class RTCUtils extends Listenable {
 
         screenObtainer.init(
             options,
-            this.getUserMediaWithConstraints.bind(this));
+            this.getUserMediaWithConstraints.bind(this),
+            getTrackSSConstraints);
 
         if (this.isDeviceListAvailable()) {
             this.enumerateDevices(ds => {

modules/RTC/ScreenObtainer.js

@@ -22,6 +22,12 @@ let chromeExtUpdateRequired = false;
 
 let gumFunction = null;
 
+/**
+ * The function used to obtain track constraints MediaTrackConstraints.
+ * @type {Function}
+ */
+let getSSConstraints = null;
+
 /**
  * The error returned by chrome when trying to start inline installation from
  * popup.
@@ -104,9 +110,10 @@ const ScreenObtainer = {
         desktopSharingChromeDisabled: false,
         desktopSharingChromeExtId: null,
         desktopSharingFirefoxDisabled: false
-    }, gum) {
+    }, gum, constraintsFunc) {
         this.options = options;
         gumFunction = gum;
+        getSSConstraints = constraintsFunc;
 
         this.obtainStream = this._createObtainStreamMethod(options);
 
@@ -167,11 +174,36 @@ const ScreenObtainer = {
                 logger.info('Chrome extension not supported until ver 34');
 
                 return null;
+            } else if (navigator.getDisplayMedia
+                        && !options.desktopSharingChromeDisabled) {
+                return (ops, onSuccess, onFailure) => {
+                    navigator.getDisplayMedia({ video: true })
+                        .then(stream => {
+                            let applyConstraintsPromise;
+
+                            if (stream
+                                && stream.getTracks()
+                                && stream.getTracks().length > 0) {
+                                applyConstraintsPromise
+                                    = stream.getTracks()[0]
+                                        .applyConstraints(getSSConstraints());
+                            } else {
+                                applyConstraintsPromise = Promise.resolve();
+                            }
+
+                            applyConstraintsPromise.then(() =>
+                                onSuccess({
+                                    stream,
+                                    sourceId: stream.id
+                                }));
+                        })
+                        .catch(() =>
+                            onFailure(new JitsiTrackError(JitsiTrackErrors
+                                .CHROME_EXTENSION_USER_CANCELED)));
+                };
             } else if (options.desktopSharingChromeDisabled
-                || options.desktopSharingChromeMethod === false
                 || !options.desktopSharingChromeExtId) {
 
-                // TODO: desktopSharingChromeMethod is deprecated, remove.
                 return null;
             }