feat(fs): return a promise from requestFullscreen and exitFullscreen …

…when we can (#6424)

src/js/player.js

@@ -1157,6 +1157,7 @@ class Player extends Component {
     this.on(this.tech_, 'pause', this.handleTechPause_);
     this.on(this.tech_, 'durationchange', this.handleTechDurationChange_);
     this.on(this.tech_, 'fullscreenchange', this.handleTechFullscreenChange_);
+    this.on(this.tech_, 'fullscreenerror', this.handleTechFullscreenError_);
     this.on(this.tech_, 'enterpictureinpicture', this.handleTechEnterPictureInPicture_);
     this.on(this.tech_, 'leavepictureinpicture', this.handleTechLeavePictureInPicture_);
     this.on(this.tech_, 'error', this.handleTechError_);
@@ -2047,6 +2048,10 @@ class Player extends Component {
     }
   }
 
+  handleTechFullscreenError_(event, err) {
+    this.trigger('fullscreenerror', err);
+  }
+
   /**
    * @private
    */
@@ -2745,6 +2750,41 @@ class Player extends Component {
    * @fires Player#fullscreenchange
    */
   requestFullscreen(fullscreenOptions) {
+    const PromiseClass = this.options_.Promise || window.Promise;
+
+    if (PromiseClass) {
+      const self = this;
+
+      return new PromiseClass((resolve, reject) => {
+        function offHandler() {
+          self.off(self.fsApi_.fullscreenerror, errorHandler);
+          self.off(self.fsApi_.fullscreenchange, changeHandler);
+        }
+        function changeHandler() {
+          offHandler();
+          resolve();
+        }
+        function errorHandler(e, err) {
+          offHandler();
+          reject(err);
+        }
+
+        self.one('fullscreenchange', changeHandler);
+        self.one('fullscreenerror', errorHandler);
+
+        const promise = self.requestFullscreenHelper_(fullscreenOptions);
+
+        if (promise) {
+          promise.then(offHandler, offHandler);
+          return promise;
+        }
+      });
+    }
+
+    return this.requestFullscreenHelper_();
+  }
+
+  requestFullscreenHelper_(fullscreenOptions) {
     let fsOptions;
 
     // Only pass fullscreen options to requestFullscreen in spec-compliant browsers.
@@ -2788,6 +2828,41 @@ class Player extends Component {
    * @fires Player#fullscreenchange
    */
   exitFullscreen() {
+    const PromiseClass = this.options_.Promise || window.Promise;
+
+    if (PromiseClass) {
+      const self = this;
+
+      return new PromiseClass((resolve, reject) => {
+        function offHandler() {
+          self.off(self.fsApi_.fullscreenerror, errorHandler);
+          self.off(self.fsApi_.fullscreenchange, changeHandler);
+        }
+        function changeHandler() {
+          offHandler();
+          resolve();
+        }
+        function errorHandler(e, err) {
+          offHandler();
+          reject(err);
+        }
+
+        self.one('fullscreenchange', changeHandler);
+        self.one('fullscreenerror', errorHandler);
+
+        const promise = self.exitFullscreenHelper_();
+
+        if (promise) {
+          promise.then(offHandler, offHandler);
+          return promise;
+        }
+      });
+    }
+
+    return this.exitFullscreenHelper_();
+  }
+
+  exitFullscreenHelper_() {
     if (this.fsApi_.requestFullscreen) {
       const promise = document[this.fsApi_.exitFullscreen]();
 

src/js/tech/html5.js

@@ -14,6 +14,7 @@ import {toTitleCase} from '../utils/string-cases.js';
 import {NORMAL as TRACK_TYPES, REMOTE} from '../tracks/track-types';
 import setupSourceset from './setup-sourceset';
 import defineLazyProperty from '../utils/define-lazy-property.js';
+import {silencePromise} from '../utils/promise';
 
 /**
  * HTML5 Media Controller - Wrapper for HTML5 Media API
@@ -652,23 +653,36 @@ class Html5 extends Tech {
     if (video.paused && video.networkState <= video.HAVE_METADATA) {
       // attempt to prime the video element for programmatic access
       // this isn't necessary on the desktop but shouldn't hurt
-      this.el_.play();
+      silencePromise(this.el_.play());
 
       // playing and pausing synchronously during the transition to fullscreen
       // can get iOS ~6.1 devices into a play/pause loop
       this.setTimeout(function() {
         video.pause();
-        video.webkitEnterFullScreen();
+        try {
+          video.webkitEnterFullScreen();
+        } catch (e) {
+          this.trigger('fullscreenerror', e);
+        }
       }, 0);
     } else {
-      video.webkitEnterFullScreen();
+      try {
+        video.webkitEnterFullScreen();
+      } catch (e) {
+        this.trigger('fullscreenerror', e);
+      }
     }
   }
 
   /**
    * Request that the `HTML5` Tech exit fullscreen.
    */
   exitFullScreen() {
+    if (!this.el_.webkitDisplayingFullscreen) {
+      this.trigger('fullscreenerror', new Error('The video is not fullscreen'));
+      return;
+    }
+
     this.el_.webkitExitFullScreen();
   }