diff --git a/externs/pictureinpicture.js b/externs/pictureinpicture.js
index 6bd16b6b4c0..8e8f5178251 100644
--- a/externs/pictureinpicture.js
+++ b/externs/pictureinpicture.js
@@ -49,3 +49,21 @@ HTMLMediaElement.prototype.webkitSupportsPresentationMode = function(mode) {};
 
 /** @type {string} */
 HTMLMediaElement.prototype.webkitPresentationMode;
+
+
+/** @const */
+var documentPictureInPicture = {};
+
+
+/**
+ * @return {!Promise}
+ */
+documentPictureInPicture.prototype.requestWindow = function(options) {};
+
+
+/** @type {Window} */
+documentPictureInPicture.prototype.window;
+
+
+/** @type {?function(!Event)} */
+documentPictureInPicture.prototype.onenter;