fix: Disable PIP if tech doesn't support it (videojs#6678)

The requestPictureInPicture API and button currently assume thta if the browser supports the PIP API, the tech supports it. This results in a broken button with certain techs, such as youtube or HTML5 with an audio el.

Checks if disablePictureInPicture is exactly false. If true it's disabled and if undefined the tech does not support it.

Fixes videojs#6398.

src/js/control-bar/picture-in-picture-toggle.js

@@ -48,10 +48,10 @@ class PictureInPictureToggle extends Button {
    * or on value returned by player.disablePictureInPicture() method.
    */
   handlePictureInPictureEnabledChange() {
-    if (!document.pictureInPictureEnabled || this.player_.disablePictureInPicture()) {
-      this.disable();
-    } else {
+    if (document.pictureInPictureEnabled && this.player_.disablePictureInPicture() === false) {
       this.enable();
+    } else {
+      this.disable();
     }
   }
 

src/js/player.js

@@ -3035,7 +3035,7 @@ class Player extends Component {
    *         A promise with a Picture-in-Picture window.
    */
   requestPictureInPicture() {
-    if ('pictureInPictureEnabled' in document) {
+    if ('pictureInPictureEnabled' in document && this.disablePictureInPicture() === false) {
       /**
        * This event fires when the player enters picture in picture mode
        *

src/js/tech/tech.js

@@ -789,12 +789,13 @@ class Tech extends Component {
   }
 
   /**
-   * A method to check for the presence of the 'disablePictureInPicture' <video> property.
+   * A method to check for the value of the 'disablePictureInPicture' <video> property.
+   * Defaults to true, as it should be considered disabled if the tech does not support pip
    *
    * @abstract
    */
   disablePictureInPicture() {
-    return false;
+    return true;
   }
 
   /**

test/unit/controls.test.js

@@ -175,7 +175,7 @@ QUnit.test('Picture-in-Picture control enabled property value should be correct
 
   assert.equal(pictureInPictureToggle.enabled_, false, 'pictureInPictureToggle button should be disabled after creation');
 
-  if ('pictureInPictureEnabled' in document) {
+  if ('pictureInPictureEnabled' in document && player.disablePictureInPicture() === false) {
     player.isInPictureInPicture(true);
     player.trigger('enterpictureinpicture');
     assert.equal(pictureInPictureToggle.enabled_, true, 'pictureInPictureToggle button should be enabled after triggering an enterpictureinpicture event');
@@ -203,7 +203,7 @@ QUnit.test('Picture-in-Picture control enabled property value should be correct
 
   assert.equal(pictureInPictureToggle.enabled_, false, 'pictureInPictureToggle button should be disabled after creation');
 
-  if ('pictureInPictureEnabled' in document) {
+  if ('pictureInPictureEnabled' in document && player.disablePictureInPicture() === false) {
     player.trigger('loadedmetadata');
     assert.equal(pictureInPictureToggle.enabled_, true, 'pictureInPictureToggle button should be enabled after triggering an loadedmetadata event');
   } else {

test/unit/player.test.js

@@ -2258,3 +2258,34 @@ QUnit.test('Should accept multiple calls to currentTime after player initializat
   assert.ok(spyCurrentTime.calledAfter(spyInitTime), 'currentTime was called on canplay event listener');
   assert.equal(player.currentTime(), 800, 'The last value passed is stored as the currentTime value');
 });
+
+QUnit.test('Should only allow requestfullscreen if the tech supports it', function(assert) {
+  const player = TestHelpers.makePlayer({});
+  let count = 0;
+
+  player.tech_.el_ = {
+    disablePictureInPicture: false,
+    requestPictureInPicture() {
+      count++;
+    }
+  };
+
+  player.tech_.requestPictureInPicture = function() {
+    return player.tech_.el_.requestPictureInPicture();
+  };
+  player.tech_.disablePictureInPicture = function() {
+    return this.el_.disablePictureInPicture;
+  };
+
+  player.requestPictureInPicture();
+  assert.equal(count, 1, 'requestPictureInPicture passed through to supporting tech');
+
+  player.tech_.el_.disablePictureInPicture = true;
+  player.requestPictureInPicture();
+  assert.equal(count, 1, 'requestPictureInPicture not passed through when disabled on tech');
+
+  delete player.tech_.el_.disablePictureInPicture;
+  player.requestPictureInPicture();
+  assert.equal(count, 1, 'requestPictureInPicture not passed through when tech does not support');
+
+});