feat(UI): Add fastSeek support for MediaSession seekTo (#9884)

externs/fastseek.js

@@ -0,0 +1,17 @@
+/*! @license
+ * Shaka Player
+ * Copyright 2016 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+
+/**
+ * @fileoverview Externs for HTMLMediaElement.fastSeek
+ * @externs
+ */
+
+/**
+ * Seeks to a given time quickly.
+ * @param {number} time
+ */
+HTMLMediaElement.prototype.fastSeek = function(time) {};

externs/mediasession.js

@@ -13,6 +13,18 @@
  */
 
 
+/**
+ * @typedef {{
+ *   action: string,
+ *   seekOffset: (number|undefined),
+ *   seekTime: (number|undefined),
+ *   fastSeek: (boolean|undefined),
+ *   enterPictureInPictureReason: (string|undefined)
+ * }}
+ */
+var MediaSessionActionDetails;
+
+
 const MediaMetadata = class {
   constructor(options) {
     /** @type {string} */
@@ -44,8 +56,7 @@ const MediaSession = class {
     this.type = type;
 
     /**
-     * @type {!function(!{action: string, seekOffset: ?number,
-     *                   seekTime: ?number})}
+     * @type {!function(!MediaSessionActionDetails)}
      */
     this.callback = callback;
   }

ui/controls.js

@@ -2357,13 +2357,17 @@ shaka.ui.Controls = class extends shaka.util.FakeEventTarget {
    * Update the video's current time based on the keyboard operations.
    *
    * @param {number} currentTime
+   * @param {boolean=} fastSeek
    * @private
    */
-  seek_(currentTime) {
+  seek_(currentTime, fastSeek = false) {
     goog.asserts.assert(
         this.seekBar_, 'Caller of seek_ must check for seekBar_ first!');
-
-    this.video_.currentTime = currentTime;
+    if (fastSeek && 'fastSeek' in this.video_) {
+      this.video_.fastSeek(currentTime);
+    } else {
+      this.video_.currentTime = currentTime;
+    }
     this.updateTimeAndSeekRange_();
   }
 
@@ -2376,9 +2380,10 @@ shaka.ui.Controls = class extends shaka.util.FakeEventTarget {
 
   /**
    * @param {number} value
+   * @param {boolean} fastSeek
    */
-  seekTo(value) {
-    this.seek_(value);
+  seekTo(value, fastSeek) {
+    this.seek_(value, fastSeek);
   }
 
   /**

ui/media_session.js

@@ -273,8 +273,7 @@ shaka.ui.MediaSession = class {
   }
 
   /**
-   * @param {!{action: string, seekOffset: ?number,
-   *         seekTime: ?number}} details
+   * @param {!MediaSessionActionDetails} details
    * @export
    */
   commonActionHandler(details) {
@@ -310,8 +309,9 @@ shaka.ui.MediaSession = class {
           break;
         }
         if (!ad || !ad.isLinear()) {
+          const fastSeek = details.fastSeek || false;
           this.controls_.seekTo(
-              this.player_.seekRange().start + details.seekTime);
+              this.player_.seekRange().start + details.seekTime, fastSeek);
         }
         break;
       case 'stop':