Improving the projection of video by setting videoElement style (#6038)

* Improving the projection of video by setting videoElement style

* use the improvement only for supported browsers and when user want it

* small fixes + add a note about browser compatibility

src/layer/VideoOverlay.js

@@ -32,7 +32,12 @@ export var VideoOverlay = ImageOverlay.extend({
 
 		// @option loop: Boolean = true
 		// Whether the video will loop back to the beginning when played.
-		loop: true
+		loop: true,
+
+		// @option keepAspectRatio: Boolean = true
+		// Whether the video will save aspect ratio after the projection.
+		// Relevant for supported browsers. Browser compatibility- https://developer.mozilla.org/en-US/docs/Web/CSS/object-fit
+		keepAspectRatio: true
 	},
 
 	_initImage: function () {
@@ -62,6 +67,7 @@ export var VideoOverlay = ImageOverlay.extend({
 
 		if (!Util.isArray(this._url)) { this._url = [this._url]; }
 
+		if (!this.options.keepAspectRatio && vid.style.hasOwnProperty('objectFit')) { vid.style['objectFit'] = 'fill'; }
 		vid.autoplay = !!this.options.autoplay;
 		vid.loop = !!this.options.loop;
 		for (var i = 0; i < this._url.length; i++) {